diff --git a/CMakeLists_files.cmake b/CMakeLists_files.cmake
index 8927a2326..38547a8d4 100644
--- a/CMakeLists_files.cmake
+++ b/CMakeLists_files.cmake
@@ -232,7 +232,11 @@ if(ENABLE_ECL_OUTPUT)
           src/opm/io/eclipse/ESmry.cpp
           src/opm/io/eclipse/OutputStream.cpp
           src/opm/io/eclipse/rst/connection.cpp
+          src/opm/io/eclipse/rst/group.cpp
           src/opm/io/eclipse/rst/header.cpp
+          src/opm/io/eclipse/rst/segment.cpp
+          src/opm/io/eclipse/rst/state.cpp
+          src/opm/io/eclipse/rst/well.cpp
           src/opm/output/eclipse/AggregateActionxData.cpp
           src/opm/output/eclipse/AggregateConnectionData.cpp
           src/opm/output/eclipse/AggregateGroupData.cpp
@@ -366,6 +370,7 @@ if(ENABLE_ECL_OUTPUT)
           tests/test_PaddedOutputString.cpp
           tests/test_Restart.cpp
           tests/test_RFT.cpp
+          tests/test_rst.cpp
           tests/test_Solution.cpp
           tests/test_Summary.cpp
           tests/test_Tables.cpp
@@ -427,6 +432,7 @@ if(ENABLE_ECL_INPUT)
     examples/opmi.cpp
     examples/opmpack.cpp
     examples/opmhash.cpp
+    tests/rst_load.cpp
   )
 endif()
 
@@ -691,7 +697,11 @@ if(ENABLE_ECL_OUTPUT)
         opm/io/eclipse/PaddedOutputString.hpp
         opm/io/eclipse/OutputStream.hpp
         opm/io/eclipse/rst/connection.hpp
+        opm/io/eclipse/rst/group.hpp
         opm/io/eclipse/rst/header.hpp
+        opm/io/eclipse/rst/segment.hpp
+        opm/io/eclipse/rst/state.hpp
+        opm/io/eclipse/rst/well.hpp
         opm/output/data/Aquifer.hpp
         opm/output/data/Cells.hpp
         opm/output/data/Solution.hpp
diff --git a/ExtraTests.cmake b/ExtraTests.cmake
index 79c33e647..bab224bfc 100644
--- a/ExtraTests.cmake
+++ b/ExtraTests.cmake
@@ -60,6 +60,7 @@ foreach (test BoxTest
 endforeach ()
 
 # opm-tests dependent tests
+opm_add_test("RST_LOAD" NO_COMPILE EXE_NAME rst_load TEST_ARGS "${PROJECT_SOURCE_DIR}/tests/SPE1_TESTCASE.UNRST")
 if(HAVE_OPM_TESTS)
   opm_add_test(parse_write ONLY_COMPILE
                SOURCES tests/parser/integration/parse_write.cpp
@@ -103,6 +104,8 @@ if(HAVE_OPM_TESTS)
   opm_add_test("SPE9_CP_GROUP2" NO_COMPILE EXE_NAME parse_write TEST_ARGS "${OPM_TESTS_ROOT}/spe9group/SPE9_CP_GROUP.DATA")
   set_property(TEST NORNE_ATW2013
                PROPERTY ENVIRONMENT "OPM_ERRORS_IGNORE=PARSE_RANDOM_SLASH")
+
+  opm_add_test("RST_LOAD_MSW" NO_COMPILE EXE_NAME rst_load TEST_ARGS "${OPM_TESTS_ROOT}/msw_3d_hfa/opm-simulation-reference/flow/3D_MSW.UNRST")
 endif()
 
 # JSON tests
diff --git a/opm/io/eclipse/rst/connection.hpp b/opm/io/eclipse/rst/connection.hpp
index 247863489..2cd92ac97 100644
--- a/opm/io/eclipse/rst/connection.hpp
+++ b/opm/io/eclipse/rst/connection.hpp
@@ -25,8 +25,8 @@ namespace RestartIO {
 
 class Header;
 
-struct Connection {
-    Connection(const int* icon, const float* scon, const double *xcon);
+struct RstConnection {
+    RstConnection(const int* icon, const float* scon, const double *xcon);
 
     int insert_index;
     std::array<int,3> ijk;
diff --git a/opm/io/eclipse/rst/group.hpp b/opm/io/eclipse/rst/group.hpp
new file mode 100644
index 000000000..22d4f74f3
--- /dev/null
+++ b/opm/io/eclipse/rst/group.hpp
@@ -0,0 +1,81 @@
+/*
+  Copyright 2020 Equinor ASA.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef RST_GROUP
+#define RST_GROUP
+
+#include <array>
+#include <vector>
+#include <string>
+
+namespace Opm {
+namespace RestartIO {
+
+class RstHeader;
+
+struct RstGroup {
+    RstGroup(const std::string* zwel,
+             const int * igrp,
+             const float * sgrp,
+             const double * xgrp);
+
+    std::string name;
+    float oil_rate_limit;
+    float water_rate_limit;
+    float gas_rate_limit;
+    float liquid_rate_limit;
+    float water_surface_limit;
+    float water_reservoir_limit;
+    float water_reinject_limit;
+    float water_voidage_limit;
+    float gas_surface_limit;
+    float gas_reservoir_limit;
+    float gas_reinject_limit;
+    float gas_voidage_limit;
+
+    double oil_production_rate;
+    double water_production_rate;
+    double gas_production_rate;
+    double liquid_production_rate;
+    double water_injection_rate;
+    double gas_injection_rate;
+    double wct;
+    double gor;
+    double oil_production_total;
+    double water_production_total;
+    double gas_production_total;
+    double voidage_production_total;
+    double water_injection_total;
+    double gas_injection_total;
+    double oil_production_potential;
+    double water_production_potential;
+    double history_total_oil_production;
+    double history_total_water_production;
+    double history_total_water_injection;
+    double history_total_gas_production;
+    double history_total_gas_injection;
+};
+
+
+}
+}
+
+
+
+
+#endif
diff --git a/opm/io/eclipse/rst/header.hpp b/opm/io/eclipse/rst/header.hpp
index ea857dd78..48e47df10 100644
--- a/opm/io/eclipse/rst/header.hpp
+++ b/opm/io/eclipse/rst/header.hpp
@@ -23,8 +23,8 @@
 namespace Opm {
 namespace RestartIO {
 
-struct Header {
-    Header(const std::vector<int>& intehead, const std::vector<bool>& logihead, const std::vector<double>& doubhead);
+struct RstHeader {
+    RstHeader(const std::vector<int>& intehead, const std::vector<bool>& logihead, const std::vector<double>& doubhead);
 
     int nx;
     int ny;
diff --git a/opm/io/eclipse/rst/segment.hpp b/opm/io/eclipse/rst/segment.hpp
new file mode 100644
index 000000000..9e03d9454
--- /dev/null
+++ b/opm/io/eclipse/rst/segment.hpp
@@ -0,0 +1,73 @@
+/*
+  Copyright 2020 Equinor ASA.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef RST_SEGMENT
+#define RST_SEGMENT
+
+#include <vector>
+
+namespace Opm {
+namespace RestartIO {
+
+struct RstSegment {
+    RstSegment(const int* iseg, const double * rseg);
+
+    int segment;
+    int outlet_segment;
+    int branch;
+    int segment_type;
+    int icd_scaling_mode;
+    int icd_open_flag;
+
+    double dist_outlet;
+    double outlet_dz;
+    double diameter;
+    double roughness;
+    double area;
+    double volume;
+    double dist_bhp_ref;
+    double bhp_ref_dz;
+    double total_flow;
+    double water_flow_fraction;
+    double gas_flow_fraction;
+    double pressure;
+    double valve_length;
+    double valve_area;
+    double valve_flow_coeff;
+    double valve_max_area;
+    double base_strength;
+    double fluid_density;
+    double fluid_viscosity;
+    double critical_water_fraction;
+    double transition_region_width;
+    double max_emulsion_ratio;
+    double max_valid_flow_rate;
+    double icd_length;
+    double valve_area_fraction;
+
+    std::vector<int> inflow_segments;
+};
+
+
+}
+}
+
+
+
+
+#endif
diff --git a/opm/io/eclipse/rst/state.hpp b/opm/io/eclipse/rst/state.hpp
new file mode 100644
index 000000000..89926e304
--- /dev/null
+++ b/opm/io/eclipse/rst/state.hpp
@@ -0,0 +1,83 @@
+/*
+  Copyright 2020 Equinor ASA.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef RST_STATE
+#define RST_STATE
+
+#include <vector>
+#include <string>
+
+#include <opm/io/eclipse/ERst.hpp>
+#include <opm/io/eclipse/rst/group.hpp>
+#include <opm/io/eclipse/rst/well.hpp>
+
+namespace Opm {
+namespace RestartIO {
+struct RstState {
+    RstState(const std::vector<int>& intehead,
+          const std::vector<bool>& logihead,
+          const std::vector<double>& doubhead,
+          const std::vector<std::string>& zgrp,
+          const std::vector<int>& igrp,
+          const std::vector<float>& sgrp,
+          const std::vector<double>& xgrp,
+          const std::vector<std::string>& zwel,
+          const std::vector<int>& iwel,
+          const std::vector<float>& swel,
+          const std::vector<double>& xwel,
+          const std::vector<int>& icon,
+          const std::vector<float>& scon,
+          const std::vector<double>& xcon);
+
+    RstState(const std::vector<int>& intehead,
+          const std::vector<bool>& logihead,
+          const std::vector<double>& doubhead,
+          const std::vector<std::string>& zgrp,
+          const std::vector<int>& igrp,
+          const std::vector<float>& sgrp,
+          const std::vector<double>& xgrp,
+          const std::vector<std::string>& zwel,
+          const std::vector<int>& iwel,
+          const std::vector<float>& swel,
+          const std::vector<double>& xwel,
+          const std::vector<int>& icon,
+          const std::vector<float>& scon,
+          const std::vector<double>& xcon,
+          const std::vector<int>& iseg,
+          const std::vector<double>& rseg);
+
+
+    static RstState load(EclIO::ERst& rst_file, int report_step);
+
+    std::vector<RstWell> wells;
+    std::vector<RstGroup> groups;
+
+private:
+    void add_groups(const RstHeader& header,
+                    const std::vector<std::string>& zgrp,
+                    const std::vector<int>& igrp,
+                    const std::vector<float>& sgrp,
+                    const std::vector<double>& xgrp);
+};
+}
+}
+
+
+
+
+#endif
diff --git a/opm/io/eclipse/rst/well.hpp b/opm/io/eclipse/rst/well.hpp
new file mode 100644
index 000000000..21ae67f74
--- /dev/null
+++ b/opm/io/eclipse/rst/well.hpp
@@ -0,0 +1,115 @@
+/*
+  Copyright 2020 Equinor ASA.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef RST_WELL
+#define RST_WELL
+
+#include <array>
+#include <vector>
+#include <string>
+#include <unordered_map>
+
+
+#include <opm/io/eclipse/rst/connection.hpp>
+#include <opm/io/eclipse/rst/segment.hpp>
+
+namespace Opm {
+namespace RestartIO {
+
+class RstHeader;
+
+struct RstWell {
+    RstWell(const RstHeader& header,
+            const std::string* zwel,
+            const int * iwel,
+            const float * swel,
+            const double * xwel,
+            const int * icon,
+            const float * scon,
+            const double * xcon);
+
+    RstWell(const RstHeader& header,
+            const std::string* zwel,
+            const int * iwel,
+            const float * swel,
+            const double * xwel,
+            const int * icon,
+            const float * scon,
+            const double * xcon,
+            const std::vector<int>& iseg,
+            const std::vector<double>& rseg);
+
+    std::string name;
+    std::array<int, 2> ij;
+    std::pair<int,int> k1k2;
+    int wtype;
+    int active_control;
+    int vfp_table;
+    int pred_requested_control;
+    int xflow;
+    int hist_requested_control;
+    int msw_index;
+    int completion_ordering;
+
+    float orat_target;
+    float wrat_target;
+    float grat_target;
+    float lrat_target;
+    float resv_target;
+    float thp_target;
+    float bhp_target_float;
+    float hist_lrat_target;
+    float hist_grat_target;
+    float hist_bhp_target;
+
+    double oil_rate;
+    double water_rate;
+    double gas_rate;
+    double liquid_rate;
+    double void_rate;
+    double flow_bhp;
+    double wct;
+    double gor;
+    double oil_total;
+    double water_total;
+    double gas_total;
+    double void_total;
+    double water_inj_total;
+    double gas_inj_total;
+    double gas_fvf;
+    double bhp_target_double;
+    double hist_oil_total;
+    double hist_wat_total;
+    double hist_gas_total;
+    double hist_water_inj_total;
+    double hist_gas_inj_total;
+    double water_void_rate;
+    double gas_void_rate;
+
+    std::vector<RstConnection> connections;
+    std::vector<RstSegment> segments;
+};
+
+
+}
+}
+
+
+
+
+#endif
diff --git a/opm/output/eclipse/VectorItems/group.hpp b/opm/output/eclipse/VectorItems/group.hpp
index 2f9027b54..7f08285c6 100644
--- a/opm/output/eclipse/VectorItems/group.hpp
+++ b/opm/output/eclipse/VectorItems/group.hpp
@@ -34,7 +34,7 @@ namespace Opm { namespace RestartIO { namespace Helpers { namespace VectorItems
         };
         
         enum inj_index : std::vector<float>::size_type {
-            waterSurfRateLimit      =  15, // Group's water surface volume injection rate target/limit
+            waterSurfRateLimit      =  15, //i Group's water surface volume injection rate target/limit
             waterResRateLimit       =  16, // Group's water reservoir volume injection rate target/limit
             waterReinjectionLimit   =  17, // Group's water reinjection fraction target/limit
             waterVoidageLimit       =  18, // Group's water voidage injection fraction target/limit
diff --git a/src/opm/io/eclipse/rst/connection.cpp b/src/opm/io/eclipse/rst/connection.cpp
index f876d7f36..7e3a00bf9 100644
--- a/src/opm/io/eclipse/rst/connection.cpp
+++ b/src/opm/io/eclipse/rst/connection.cpp
@@ -26,7 +26,7 @@ namespace VI = ::Opm::RestartIO::Helpers::VectorItems;
 namespace Opm {
 namespace RestartIO {
 
-Connection::Connection(const int* icon, const float* scon, const double* xcon) :
+RstConnection::RstConnection(const int* icon, const float* scon, const double* xcon) :
     insert_index(icon[VI::IConn::SeqIndex]),
     ijk({icon[VI::IConn::CellI] - 1, icon[VI::IConn::CellJ] - 1, icon[VI::IConn::CellK] - 1}),
     status(icon[VI::IConn::ConnStat]),
diff --git a/src/opm/io/eclipse/rst/group.cpp b/src/opm/io/eclipse/rst/group.cpp
new file mode 100644
index 000000000..b6464a66f
--- /dev/null
+++ b/src/opm/io/eclipse/rst/group.cpp
@@ -0,0 +1,75 @@
+/*
+  Copyright 2020 Equinor ASA.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <opm/parser/eclipse/Utility/String.hpp>
+
+#include <opm/io/eclipse/rst/header.hpp>
+#include <opm/io/eclipse/rst/group.hpp>
+
+#include <opm/output/eclipse/VectorItems/group.hpp>
+
+
+namespace VI = ::Opm::RestartIO::Helpers::VectorItems;
+
+namespace Opm {
+namespace RestartIO {
+
+RstGroup::RstGroup(const std::string* zwel,
+                   const int *,
+                   const float * sgrp,
+                   const double * xgrp) :
+    name(trim_copy(zwel[0])),
+    oil_rate_limit(sgrp[VI::SGroup::OilRateLimit]),
+    water_rate_limit(sgrp[VI::SGroup::WatRateLimit]),
+    gas_rate_limit(sgrp[VI::SGroup::GasRateLimit]),
+    liquid_rate_limit(sgrp[VI::SGroup::LiqRateLimit]),
+    water_surface_limit(sgrp[VI::SGroup::waterSurfRateLimit]),
+    water_reservoir_limit(sgrp[VI::SGroup::waterResRateLimit]),
+    water_reinject_limit(sgrp[VI::SGroup::waterReinjectionLimit]),
+    water_voidage_limit(sgrp[VI::SGroup::waterVoidageLimit]),
+    gas_surface_limit(sgrp[VI::SGroup::gasSurfRateLimit]),
+    gas_reservoir_limit(sgrp[VI::SGroup::gasResRateLimit]),
+    gas_reinject_limit(sgrp[VI::SGroup::gasReinjectionLimit]),
+    gas_voidage_limit(sgrp[VI::SGroup::gasVoidageLimit]),
+    oil_production_rate(xgrp[VI::XGroup::OilPrRate]),
+    water_production_rate(xgrp[VI::XGroup::WatPrRate]),
+    gas_production_rate(xgrp[VI::XGroup::GasPrRate]),
+    liquid_production_rate(xgrp[VI::XGroup::LiqPrRate]),
+    water_injection_rate(xgrp[VI::XGroup::WatInjRate]),
+    gas_injection_rate(xgrp[VI::XGroup::GasInjRate]),
+    wct(xgrp[VI::XGroup::WatCut]),
+    gor(xgrp[VI::XGroup::GORatio]),
+    oil_production_total(xgrp[VI::XGroup::OilPrTotal]),
+    water_production_total(xgrp[VI::XGroup::WatPrTotal]),
+    gas_production_total(xgrp[VI::XGroup::GasPrTotal]),
+    voidage_production_total(xgrp[VI::XGroup::VoidPrTotal]),
+    water_injection_total(xgrp[VI::XGroup::WatInjTotal]),
+    gas_injection_total(xgrp[VI::XGroup::GasInjTotal]),
+    oil_production_potential(xgrp[VI::XGroup::OilPrPot]),
+    water_production_potential(xgrp[VI::XGroup::WatPrPot]),
+    history_total_oil_production(xgrp[VI::XGroup::HistOilPrTotal]),
+    history_total_water_production(xgrp[VI::XGroup::HistWatPrTotal]),
+    history_total_water_injection(xgrp[VI::XGroup::HistWatInjTotal]),
+    history_total_gas_production(xgrp[VI::XGroup::HistGasPrTotal]),
+    history_total_gas_injection(xgrp[VI::XGroup::HistGasInjTotal])
+{
+}
+
+
+}
+}
diff --git a/src/opm/io/eclipse/rst/header.cpp b/src/opm/io/eclipse/rst/header.cpp
index 78b6a5ce5..f31bcf1e9 100644
--- a/src/opm/io/eclipse/rst/header.cpp
+++ b/src/opm/io/eclipse/rst/header.cpp
@@ -26,7 +26,7 @@ namespace VI = ::Opm::RestartIO::Helpers::VectorItems;
 namespace Opm {
 namespace RestartIO {
 
-Header::Header(const std::vector<int>& intehead, const std::vector<bool>& logihead, const std::vector<double>& doubhead) :
+RstHeader::RstHeader(const std::vector<int>& intehead, const std::vector<bool>& logihead, const std::vector<double>& doubhead) :
     nx(intehead[VI::intehead::NX]),
     ny(intehead[VI::intehead::NY]),
     nz(intehead[VI::intehead::NZ]),
diff --git a/src/opm/io/eclipse/rst/segment.cpp b/src/opm/io/eclipse/rst/segment.cpp
new file mode 100644
index 000000000..0e348226e
--- /dev/null
+++ b/src/opm/io/eclipse/rst/segment.cpp
@@ -0,0 +1,66 @@
+/*
+  Copyright 2020 Equinor ASA.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include <stdio.h>
+
+#include <opm/io/eclipse/rst/segment.hpp>
+#include <opm/output/eclipse/VectorItems/msw.hpp>
+
+namespace VI = ::Opm::RestartIO::Helpers::VectorItems;
+
+namespace Opm {
+namespace RestartIO {
+
+RstSegment::RstSegment(const int * iseg, const double * rseg) :
+    segment(iseg[VI::ISeg::SegNo]),
+    outlet_segment(iseg[VI::ISeg::OutSeg]),
+    branch(iseg[VI::ISeg::BranchNo]),
+    segment_type(iseg[VI::ISeg::SegmentType]),
+    icd_scaling_mode(iseg[VI::ISeg::ICDScalingMode]),
+    icd_open_flag(iseg[VI::ISeg::ICDOpenShutFlag]),
+    dist_outlet(rseg[VI::RSeg::DistOutlet]),
+    outlet_dz(rseg[VI::RSeg::OutletDepthDiff]),
+    diameter(rseg[VI::RSeg::SegDiam]),
+    roughness(rseg[VI::RSeg::SegRough]),
+    area(rseg[VI::RSeg::SegArea]),
+    volume(rseg[VI::RSeg::SegVolume]),
+    dist_bhp_ref(rseg[VI::RSeg::DistBHPRef]),
+    bhp_ref_dz(rseg[VI::RSeg::DepthBHPRef]),
+    total_flow(rseg[VI::RSeg::TotFlowRate]),
+    water_flow_fraction(rseg[VI::RSeg::WatFlowFract]),
+    gas_flow_fraction(rseg[VI::RSeg::GasFlowFract]),
+    pressure(rseg[VI::RSeg::Pressure]),
+    valve_length(rseg[VI::RSeg::ValveLength]),
+    valve_area(rseg[VI::RSeg::ValveArea]),
+    valve_flow_coeff(rseg[VI::RSeg::ValveFlowCoeff]),
+    valve_max_area(rseg[VI::RSeg::ValveMaxArea]),
+    base_strength(rseg[VI::RSeg::DeviceBaseStrength]),
+    fluid_density(rseg[VI::RSeg::CalibrFluidDensity]),
+    fluid_viscosity(rseg[VI::RSeg::CalibrFluidViscosity]),
+    critical_water_fraction(rseg[VI::RSeg::CriticalWaterFraction]),
+    transition_region_width(rseg[VI::RSeg::TransitionRegWidth]),
+    max_emulsion_ratio(rseg[VI::RSeg::MaxEmulsionRatio]),
+    max_valid_flow_rate(rseg[VI::RSeg::MaxValidFlowRate]),
+    icd_length(rseg[VI::RSeg::ICDLength]),
+    valve_area_fraction(rseg[VI::RSeg::ValveAreaFraction])
+{
+    if (iseg[VI::ISeg::InSegCurBranch] != 0)
+        this->inflow_segments.push_back(iseg[VI::ISeg::InSegCurBranch]);
+}
+
+}
+}
diff --git a/src/opm/io/eclipse/rst/state.cpp b/src/opm/io/eclipse/rst/state.cpp
new file mode 100644
index 000000000..173d55488
--- /dev/null
+++ b/src/opm/io/eclipse/rst/state.cpp
@@ -0,0 +1,172 @@
+/*
+  Copyright 2020 Equinor ASA.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <opm/io/eclipse/rst/header.hpp>
+#include <opm/io/eclipse/rst/connection.hpp>
+#include <opm/io/eclipse/rst/well.hpp>
+#include <opm/io/eclipse/rst/state.hpp>
+
+#include <opm/output/eclipse/VectorItems/connection.hpp>
+#include <opm/output/eclipse/VectorItems/well.hpp>
+
+namespace VI = ::Opm::RestartIO::Helpers::VectorItems;
+
+namespace Opm {
+namespace RestartIO {
+
+RstState::RstState(const std::vector<int>& intehead,
+                   const std::vector<bool>& logihead,
+                   const std::vector<double>& doubhead,
+                   const std::vector<std::string>& zgrp,
+                   const std::vector<int>& igrp,
+                   const std::vector<float>& sgrp,
+                   const std::vector<double>& xgrp,
+                   const std::vector<std::string>& zwel,
+                   const std::vector<int>& iwel,
+                   const std::vector<float>& swel,
+                   const std::vector<double>& xwel,
+                   const std::vector<int>& icon,
+                   const std::vector<float>& scon,
+                   const std::vector<double>& xcon)
+{
+    RstHeader header(intehead, logihead, doubhead);
+    this->add_groups(header, zgrp, igrp, sgrp, xgrp);
+
+    for (int iw = 0; iw < header.num_wells; iw++) {
+        std::size_t zwel_offset = iw * header.nzwelz;
+        std::size_t iwel_offset = iw * header.niwelz;
+        std::size_t swel_offset = iw * header.nswelz;
+        std::size_t xwel_offset = iw * header.nxwelz;
+        std::size_t icon_offset = iw * header.niconz * header.ncwmax;
+        std::size_t scon_offset = iw * header.nsconz * header.ncwmax;
+        std::size_t xcon_offset = iw * header.nxconz * header.ncwmax;
+
+        this->wells.emplace_back(header,
+                                 zwel.data() + zwel_offset,
+                                 iwel.data() + iwel_offset,
+                                 swel.data() + swel_offset,
+                                 xwel.data() + xwel_offset,
+                                 icon.data() + icon_offset,
+                                 scon.data() + scon_offset,
+                                 xcon.data() + xcon_offset);
+
+        if (this->wells.back().msw_index)
+            throw std::logic_error("MSW data not accounted for in this constructor");
+    }
+}
+
+RstState::RstState(const std::vector<int>& intehead,
+             const std::vector<bool>& logihead,
+             const std::vector<double>& doubhead,
+             const std::vector<std::string>& zgrp,
+             const std::vector<int>& igrp,
+             const std::vector<float>& sgrp,
+             const std::vector<double>& xgrp,
+             const std::vector<std::string>& zwel,
+             const std::vector<int>& iwel,
+             const std::vector<float>& swel,
+             const std::vector<double>& xwel,
+             const std::vector<int>& icon,
+             const std::vector<float>& scon,
+             const std::vector<double>& xcon,
+             const std::vector<int>& iseg,
+             const std::vector<double>& rseg)
+{
+    RstHeader header(intehead, logihead, doubhead);
+    this->add_groups(header, zgrp, igrp, sgrp, xgrp);
+
+    for (int iw = 0; iw < header.num_wells; iw++) {
+        std::size_t zwel_offset = iw * header.nzwelz;
+        std::size_t iwel_offset = iw * header.niwelz;
+        std::size_t swel_offset = iw * header.nswelz;
+        std::size_t xwel_offset = iw * header.nxwelz;
+        std::size_t icon_offset = iw * header.niconz * header.ncwmax;
+        std::size_t scon_offset = iw * header.nsconz * header.ncwmax;
+        std::size_t xcon_offset = iw * header.nxconz * header.ncwmax;
+
+        this->wells.emplace_back(header,
+                                 zwel.data() + zwel_offset,
+                                 iwel.data() + iwel_offset,
+                                 swel.data() + swel_offset,
+                                 xwel.data() + xwel_offset,
+                                 icon.data() + icon_offset,
+                                 scon.data() + scon_offset,
+                                 xcon.data() + xcon_offset,
+                                 iseg,
+                                 rseg);
+    }
+}
+
+void RstState::add_groups(const RstHeader& header,
+                          const std::vector<std::string>& zgrp,
+                          const std::vector<int>& igrp,
+                          const std::vector<float>& sgrp,
+                          const std::vector<double>& xgrp)
+{
+    for (int ig=0; ig < header.ngroup; ig++) {
+        std::size_t zgrp_offset = ig * header.nzgrpz;
+        std::size_t igrp_offset = ig * header.nigrpz;
+        std::size_t sgrp_offset = ig * header.nsgrpz;
+        std::size_t xgrp_offset = ig * header.nxgrpz;
+
+        this->groups.emplace_back(zgrp.data() + zgrp_offset,
+                                  igrp.data() + igrp_offset,
+                                  sgrp.data() + sgrp_offset,
+                                  xgrp.data() + xgrp_offset);
+    }
+}
+
+
+RstState RstState::load(EclIO::ERst& rst_file, int report_step) {
+    rst_file.loadReportStepNumber(report_step);
+    const auto& intehead = rst_file.getRst<int>("INTEHEAD", report_step, 0);
+    const auto& logihead = rst_file.getRst<bool>("LOGIHEAD", report_step, 0);
+    const auto& doubhead = rst_file.getRst<double>("DOUBHEAD", report_step, 0);
+
+    const auto& zgrp = rst_file.getRst<std::string>("ZGRP", report_step, 0);
+    const auto& igrp = rst_file.getRst<int>("IGRP", report_step, 0);
+    const auto& sgrp = rst_file.getRst<float>("SGRP", report_step, 0);
+    const auto& xgrp = rst_file.getRst<double>("XGRP", report_step, 0);
+
+    const auto& zwel = rst_file.getRst<std::string>("ZWEL", report_step, 0);
+    const auto& iwel = rst_file.getRst<int>("IWEL", report_step, 0);
+    const auto& swel = rst_file.getRst<float>("SWEL", report_step, 0);
+    const auto& xwel = rst_file.getRst<double>("XWEL", report_step, 0);
+
+    const auto& icon = rst_file.getRst<int>("ICON", report_step, 0);
+    const auto& scon = rst_file.getRst<float>("SCON", report_step, 0);
+    const auto& xcon = rst_file.getRst<double>("XCON", report_step, 0);
+
+    if (rst_file.hasKey("ISEG")) {
+        const auto& iseg = rst_file.getRst<int>("ISEG", report_step, 0);
+        const auto& rseg = rst_file.getRst<double>("RSEG", report_step, 0);
+
+        return RstState(intehead, logihead, doubhead,
+                     zgrp, igrp, sgrp, xgrp,
+                     zwel, iwel, swel, xwel,
+                     icon, scon, xcon,
+                     iseg, rseg);
+    } else
+        return RstState(intehead, logihead, doubhead,
+                     zgrp, igrp, sgrp, xgrp,
+                     zwel, iwel, swel, xwel,
+                     icon, scon, xcon);
+}
+
+}
+}
diff --git a/src/opm/io/eclipse/rst/well.cpp b/src/opm/io/eclipse/rst/well.cpp
new file mode 100644
index 000000000..a04237df8
--- /dev/null
+++ b/src/opm/io/eclipse/rst/well.cpp
@@ -0,0 +1,133 @@
+/*
+  Copyright 2020 Equinor ASA.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <opm/parser/eclipse/Utility/String.hpp>
+
+#include <opm/io/eclipse/rst/header.hpp>
+#include <opm/io/eclipse/rst/connection.hpp>
+#include <opm/io/eclipse/rst/well.hpp>
+
+#include <opm/output/eclipse/VectorItems/connection.hpp>
+#include <opm/output/eclipse/VectorItems/msw.hpp>
+#include <opm/output/eclipse/VectorItems/well.hpp>
+
+
+namespace VI = ::Opm::RestartIO::Helpers::VectorItems;
+
+namespace Opm {
+namespace RestartIO {
+
+RstWell::RstWell(const RstHeader& header,
+                 const std::string* zwel,
+                 const int * iwel,
+                 const float * swel,
+                 const double * xwel,
+                 const int * icon,
+                 const float * scon,
+                 const double * xcon) :
+    name(trim_copy(zwel[0])),
+    ij({iwel[VI::IWell::IHead] - 1, iwel[VI::IWell::JHead] - 1}),
+    k1k2(std::make_pair(iwel[VI::IWell::FirstK] - 1, iwel[VI::IWell::LastK] - 1)),
+    wtype(iwel[VI::IWell::WType]),
+    active_control(iwel[VI::IWell::ActWCtrl]),
+    vfp_table(iwel[VI::IWell::VFPTab]),
+    pred_requested_control(iwel[VI::IWell::PredReqWCtrl]),
+    xflow(iwel[VI::IWell::XFlow]),
+    hist_requested_control(iwel[VI::IWell::HistReqWCtrl]),
+    msw_index(iwel[VI::IWell::MsWID]),
+    completion_ordering(iwel[VI::IWell::CompOrd]),
+    orat_target(swel[VI::SWell::OilRateTarget]),
+    wrat_target(swel[VI::SWell::WatRateTarget]),
+    grat_target(swel[VI::SWell::GasRateTarget]),
+    lrat_target(swel[VI::SWell::LiqRateTarget]),
+    resv_target(swel[VI::SWell::ResVRateTarget]),
+    thp_target(swel[VI::SWell::THPTarget]),
+    bhp_target_float(swel[VI::SWell::BHPTarget]),
+    hist_lrat_target(swel[VI::SWell::HistLiqRateTarget]),
+    hist_grat_target(swel[VI::SWell::HistGasRateTarget]),
+    hist_bhp_target(swel[VI::SWell::HistBHPTarget]),
+    oil_rate(xwel[VI::XWell::OilPrRate]),
+    water_rate(xwel[VI::XWell::WatPrRate]),
+    gas_rate(xwel[VI::XWell::GasPrRate]),
+    liquid_rate(xwel[VI::XWell::LiqPrRate]),
+    void_rate(xwel[VI::XWell::VoidPrRate]),
+    flow_bhp(xwel[VI::XWell::FlowBHP]),
+    wct(xwel[VI::XWell::WatCut]),
+    gor(xwel[VI::XWell::GORatio]),
+    oil_total(xwel[VI::XWell::OilPrTotal]),
+    water_total(xwel[VI::XWell::WatPrTotal]),
+    gas_total(xwel[VI::XWell::GasPrTotal]),
+    void_total(xwel[VI::XWell::VoidPrTotal]),
+    water_inj_total(xwel[VI::XWell::WatInjTotal]),
+    gas_inj_total(xwel[VI::XWell::GasInjTotal]),
+    gas_fvf(xwel[VI::XWell::GasFVF]),
+    bhp_target_double(xwel[VI::XWell::BHPTarget]),
+    hist_oil_total(xwel[VI::XWell::HistOilPrTotal]),
+    hist_wat_total(xwel[VI::XWell::HistWatPrTotal]),
+    hist_gas_total(xwel[VI::XWell::HistGasPrTotal]),
+    hist_water_inj_total(xwel[VI::XWell::HistWatInjTotal]),
+    hist_gas_inj_total(xwel[VI::XWell::HistGasInjTotal]),
+    water_void_rate(xwel[VI::XWell::WatVoidPrRate]),
+    gas_void_rate(xwel[VI::XWell::GasVoidPrRate])
+{
+    for (int ic = 0; ic < iwel[VI::IWell::NConn]; ic++) {
+        std::size_t icon_offset = ic * header.niconz;
+        std::size_t scon_offset = ic * header.nsconz;
+        std::size_t xcon_offset = ic * header.nxconz;
+        this->connections.emplace_back( icon + icon_offset, scon + scon_offset, xcon + xcon_offset);
+    }
+}
+
+
+
+RstWell::RstWell(const RstHeader& header,
+                 const std::string* zwel,
+                 const int * iwel,
+                 const float * swel,
+                 const double * xwel,
+                 const int * icon,
+                 const float * scon,
+                 const double * xcon,
+                 const std::vector<int>& iseg,
+                 const std::vector<double>& rseg) :
+    RstWell(header, zwel, iwel, swel, xwel, icon, scon, xcon)
+{
+
+    if (this->msw_index) {
+        std::unordered_map<int, std::size_t> segment_map;
+        for (int is=0; is < header.nsegmx; is++) {
+            std::size_t iseg_offset = header.nisegz * (is + (this->msw_index - 1) * header.nsegmx);
+            std::size_t rseg_offset = header.nrsegz * (is + (this->msw_index - 1) * header.nsegmx);
+            auto segment_number = iseg[iseg_offset + VI::ISeg::SegNo];
+            if (segment_number != 0) {
+                segment_map.insert({segment_number, this->segments.size()});
+                this->segments.emplace_back( iseg.data() + iseg_offset, rseg.data() + rseg_offset);
+            }
+        }
+
+        for (auto& segment : this->segments) {
+            if (segment.outlet_segment != 0) {
+                auto& outlet_segment = this->segments[ segment_map[segment.outlet_segment] ];
+                outlet_segment.inflow_segments.push_back(segment.segment);
+            }
+        }
+    }
+}
+
+}
+}
diff --git a/tests/rst_load.cpp b/tests/rst_load.cpp
new file mode 100644
index 000000000..211ed5179
--- /dev/null
+++ b/tests/rst_load.cpp
@@ -0,0 +1,34 @@
+/*
+  Copyright 2020 Equinor ASA
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <opm/io/eclipse/rst/state.hpp>
+#include <opm/io/eclipse/ERst.hpp>
+
+
+
+
+int main(int argc, char ** argv) {
+    for (int iarg = 1; iarg < argc; iarg++) {
+        Opm::EclIO::ERst rst_file(argv[iarg]);
+        for (int report_step : rst_file.listOfReportStepNumbers()) {
+            if (report_step > 0)
+                const auto& state = Opm::RestartIO::RstState::load(rst_file, report_step);
+        }
+    }
+}
diff --git a/tests/test_AggregateConnectionData.cpp b/tests/test_AggregateConnectionData.cpp
index 992cc2f01..2e62a06f3 100644
--- a/tests/test_AggregateConnectionData.cpp
+++ b/tests/test_AggregateConnectionData.cpp
@@ -803,7 +803,7 @@ BOOST_AUTO_TEST_CASE(TestRestartIOConnection) {
     const auto ih = MockIH {static_cast<int>(simCase.sched.getWells(rptStep).size())};
     const Opm::data::WellRates wrc = wr();
 
-    Opm::RestartIO::Header header(ih.value, lh, dh);
+    Opm::RestartIO::RstHeader header(ih.value, lh, dh);
     auto conn = Opm::RestartIO::Helpers::AggregateConnectionData{ih.value};
     conn.captureDeclaredConnData(simCase.sched,
                                  simCase.grid,
@@ -816,7 +816,7 @@ BOOST_AUTO_TEST_CASE(TestRestartIOConnection) {
     const auto scon = conn.getSConn();
     const auto xcon = conn.getXConn();
 
-    std::vector<Opm::RestartIO::Connection> connections;
+    std::vector<Opm::RestartIO::RstConnection> connections;
     for (int iw = 0; iw < header.num_wells; iw++) {
         for (int ic = 0; ic < header.ncwmax; ic++) {
             std::size_t icon_offset = header.niconz * (header.ncwmax * iw + ic);
diff --git a/tests/test_AggregateMSWData.cpp b/tests/test_AggregateMSWData.cpp
index e23e4be76..5bf34795b 100644
--- a/tests/test_AggregateMSWData.cpp
+++ b/tests/test_AggregateMSWData.cpp
@@ -29,6 +29,7 @@
 
 #include <opm/output/data/Wells.hpp>
 
+#include <opm/io/eclipse/rst/segment.hpp>
 #include <opm/parser/eclipse/Deck/Deck.hpp>
 #include <opm/parser/eclipse/Parser/Parser.hpp>
 #include <opm/parser/eclipse/EclipseState/EclipseState.hpp>
@@ -819,4 +820,32 @@ BOOST_AUTO_TEST_CASE (Declared_MSW_Data)
 }
 
 
+BOOST_AUTO_TEST_CASE(MSW_RST) {
+    const auto simCase = SimulationCase{first_sim()};
+
+    // Report Step 1: 2115-01-01 --> 2015-01-03
+    const auto rptStep = std::size_t{1};
+
+    const auto ih = MockIH {
+                            static_cast<int>(simCase.sched.getWells(rptStep).size())
+    };
+
+    const auto smry = sim_state();
+    const Opm::data::WellRates wrc = wr();
+    auto amswd = Opm::RestartIO::Helpers::AggregateMSWData{ih.value};
+    amswd.captureDeclaredMSWData(simCase.sched,
+                                 rptStep,
+                                 simCase.es.getUnits(),
+                                 ih.value,
+                                 simCase.grid,
+                                 smry,
+                                 wrc
+                                 );
+    const auto& iseg = amswd.getISeg();
+    const auto& rseg = amswd.getRSeg();
+    auto segment = Opm::RestartIO::RstSegment(iseg.data(), rseg.data());
+}
+
+
+
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/tests/test_AggregateWellData.cpp b/tests/test_AggregateWellData.cpp
index e8b500466..2ff5d8e0b 100644
--- a/tests/test_AggregateWellData.cpp
+++ b/tests/test_AggregateWellData.cpp
@@ -23,10 +23,15 @@
 #include <boost/test/unit_test.hpp>
 
 #include <opm/output/eclipse/AggregateWellData.hpp>
+#include <opm/output/eclipse/AggregateConnectionData.hpp>
 
 #include <opm/parser/eclipse/EclipseState/Schedule/SummaryState.hpp>
 #include <opm/output/eclipse/VectorItems/intehead.hpp>
 #include <opm/output/eclipse/VectorItems/well.hpp>
+#include <opm/output/eclipse/WriteRestartHelpers.hpp>
+
+#include <opm/io/eclipse/rst/well.hpp>
+#include <opm/io/eclipse/rst/header.hpp>
 
 #include <opm/output/data/Wells.hpp>
 
@@ -342,17 +347,21 @@ TSTEP            -- 8
 
         return xw;
     }
-}
+
+
+} // namespace
 
 struct SimulationCase
 {
     explicit SimulationCase(const Opm::Deck& deck)
         : es   { deck }
+        , grid { deck }
         , sched{ deck, es }
     {}
 
     // Order requirement: 'es' must be declared/initialised before 'sched'.
     Opm::EclipseState es;
+    Opm::EclipseGrid  grid;
     Opm::Schedule     sched;
 };
 
@@ -774,4 +783,76 @@ BOOST_AUTO_TEST_CASE (Dynamic_Well_Data_Step2)
     }
 }
 
+
+BOOST_AUTO_TEST_CASE(WELL_POD) {
+    const auto simCase = SimulationCase{first_sim()};
+    const auto& units = simCase.es.getUnits();
+    // Report Step 2: 2011-01-20 --> 2013-06-15
+    const auto rptStep = std::size_t{2};
+    const auto sim_step = rptStep - 1;
+    Opm::SummaryState sumState(std::chrono::system_clock::now());
+
+    const auto ih = Opm::RestartIO::Helpers::createInteHead(simCase.es,
+                                                            simCase.grid,
+                                                            simCase.sched,
+                                                            0,
+                                                            sim_step,
+                                                            sim_step);
+
+    auto wellData = Opm::RestartIO::Helpers::AggregateWellData(ih);
+    wellData.captureDeclaredWellData(simCase.sched, units, sim_step, sumState, ih);
+    wellData.captureDynamicWellData(simCase.sched, sim_step, {} , sumState);
+
+    auto connectionData = Opm::RestartIO::Helpers::AggregateConnectionData(ih);
+    connectionData.captureDeclaredConnData(simCase.sched, simCase.grid, units, {} , sim_step);
+
+    const auto& iwel = wellData.getIWell();
+    const auto& swel = wellData.getSWell();
+    const auto& xwel = wellData.getXWell();
+    const auto& zwel8 = wellData.getZWell();
+
+    const auto& icon = connectionData.getIConn();
+    const auto& scon = connectionData.getSConn();
+    const auto& xcon = connectionData.getXConn();
+
+    Opm::RestartIO::RstHeader header(ih, std::vector<bool>(100), std::vector<double>(1000));
+    std::vector<Opm::RestartIO::RstWell> wells;
+    std::vector<std::string> zwel;
+    for (const auto& s8: zwel8)
+        zwel.push_back(s8.c_str());
+
+    for (auto iw = 0; iw < header.num_wells; iw++) {
+        std::size_t zwel_offset = header.nzwelz * iw;
+        std::size_t iwel_offset = header.niwelz * iw;
+        std::size_t swel_offset = header.nswelz * iw;
+        std::size_t xwel_offset = header.nxwelz * iw;
+        std::size_t icon_offset = header.niconz * header.ncwmax * iw;
+        std::size_t scon_offset = header.nsconz * header.ncwmax * iw;
+        std::size_t xcon_offset = header.nxconz * header.ncwmax * iw;
+
+        wells.emplace_back(header,
+                           zwel.data() + zwel_offset,
+                           iwel.data() + iwel_offset,
+                           swel.data() + swel_offset,
+                           xwel.data() + xwel_offset,
+                           icon.data() + icon_offset,
+                           scon.data() + scon_offset,
+                           xcon.data() + xcon_offset);
+
+    }
+    // Well OP2
+    const auto& well2 = wells[1];
+    BOOST_CHECK_EQUAL(well2.k1k2.first, 1);
+    BOOST_CHECK_EQUAL(well2.k1k2.second, 1);
+    BOOST_CHECK_EQUAL(well2.ij[0], 8);
+    BOOST_CHECK_EQUAL(well2.ij[1], 8);
+    BOOST_CHECK_EQUAL(well2.name, "OP_2");
+
+    BOOST_CHECK_EQUAL(well2.connections.size(), 1);
+    const auto& conn1 = well2.connections[0];
+    BOOST_CHECK_EQUAL(conn1.ijk[0], 8);
+    BOOST_CHECK_EQUAL(conn1.ijk[1], 8);
+    BOOST_CHECK_EQUAL(conn1.ijk[2], 1);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/tests/test_InteHEAD.cpp b/tests/test_InteHEAD.cpp
index e4bffe5a0..022c27640 100755
--- a/tests/test_InteHEAD.cpp
+++ b/tests/test_InteHEAD.cpp
@@ -571,7 +571,7 @@ BOOST_AUTO_TEST_CASE(TestHeader) {
          .regionDimensions({ntfip, nmfipr, 0,0,0})
          .ngroups({ngroup});
 
-    Opm::RestartIO::Header header(ih.data(), std::vector<bool>(100), std::vector<double>(1000));
+    Opm::RestartIO::RstHeader header(ih.data(), std::vector<bool>(100), std::vector<double>(1000));
     BOOST_CHECK_EQUAL(header.nx, nx);
     BOOST_CHECK_EQUAL(header.ny, ny);
     BOOST_CHECK_EQUAL(header.nactive, nactive);
diff --git a/tests/test_rst.cpp b/tests/test_rst.cpp
new file mode 100644
index 000000000..798d6c7d2
--- /dev/null
+++ b/tests/test_rst.cpp
@@ -0,0 +1,314 @@
+/*
+  Copyright 2020 Equinor ASA
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#define BOOST_TEST_MODULE test_rst
+
+#include <boost/test/unit_test.hpp>
+
+#include <vector>
+
+#include <opm/output/eclipse/WriteRestartHelpers.hpp>
+#include <opm/output/eclipse/AggregateWellData.hpp>
+#include <opm/output/eclipse/AggregateConnectionData.hpp>
+#include <opm/output/eclipse/AggregateGroupData.hpp>
+
+#include <opm/parser/eclipse/EclipseState/Schedule/SummaryState.hpp>
+#include <opm/output/eclipse/VectorItems/intehead.hpp>
+#include <opm/output/eclipse/VectorItems/well.hpp>
+#include <opm/output/eclipse/WriteRestartHelpers.hpp>
+
+#include <opm/output/data/Wells.hpp>
+
+#include <opm/parser/eclipse/Deck/Deck.hpp>
+#include <opm/parser/eclipse/Parser/Parser.hpp>
+#include <opm/parser/eclipse/EclipseState/EclipseState.hpp>
+#include <opm/parser/eclipse/EclipseState/Schedule/Schedule.hpp>
+
+#include <opm/io/eclipse/rst/connection.hpp>
+#include <opm/io/eclipse/rst/header.hpp>
+#include <opm/io/eclipse/rst/group.hpp>
+#include <opm/io/eclipse/rst/segment.hpp>
+#include <opm/io/eclipse/rst/well.hpp>
+#include <opm/io/eclipse/rst/state.hpp>
+
+namespace {
+    Opm::Deck first_sim()
+    {
+        // Mostly copy of tests/FIRST_SIM.DATA
+        const auto input = std::string {
+            R"~(
+RUNSPEC
+OIL
+GAS
+WATER
+DISGAS
+VAPOIL
+UNIFOUT
+UNIFIN
+DIMENS
+ 10 10 10 /
+
+GRID
+DXV
+10*0.25 /
+DYV
+10*0.25 /
+DZV
+10*0.25 /
+TOPS
+100*0.25 /
+
+PORO
+1000*0.2 /
+
+SOLUTION
+RESTART
+FIRST_SIM 1/
+
+
+START             -- 0
+1 NOV 1979 /
+
+SCHEDULE
+SKIPREST
+RPTRST
+BASIC=1
+/
+DATES             -- 1
+ 10  OKT 2008 /
+/
+WELSPECS
+      'OP_1'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  /
+      'OP_2'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  /
+/
+COMPDAT
+      'OP_1'  9  9   1   1 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 /
+      'OP_2'  9  9   2   2 'OPEN' 1*   46.825   0.311  4332.346 1*  1*  'X'  22.123 /
+      'OP_1'  9  9   3   3 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 /
+/
+WCONPROD
+      'OP_1' 'OPEN' 'ORAT' 20000  4* 1000 /
+/
+WCONINJE
+      'OP_2' 'GAS' 'OPEN' 'RATE' 100 200 400 /
+/
+
+DATES             -- 2
+ 20  JAN 2011 /
+/
+WELSPECS
+      'OP_3'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  /
+/
+COMPDAT
+      'OP_3'  9  9   1   1 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 /
+/
+WCONPROD
+      'OP_3' 'OPEN' 'ORAT' 20000  4* 1000 /
+/
+WCONINJE
+      'OP_2' 'WATER' 'OPEN' 'RATE' 100 200 400 /
+/
+
+DATES             -- 3
+ 15  JUN 2013 /
+/
+COMPDAT
+      'OP_2'  9  9   3  9 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 /
+      'OP_1'  9  9   7  7 'SHUT' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 /
+/
+
+DATES             -- 4
+ 22  APR 2014 /
+/
+WELSPECS
+      'OP_4'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  /
+/
+COMPDAT
+      'OP_4'  9  9   3  9 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 /
+      'OP_3'  9  9   3  9 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 /
+/
+WCONPROD
+      'OP_4' 'OPEN' 'ORAT' 20000  4* 1000 /
+/
+
+DATES             -- 5
+ 30  AUG 2014 /
+/
+WELSPECS
+      'OP_5'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  /
+/
+COMPDAT
+      'OP_5'  9  9   3  9 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 /
+/
+WCONPROD
+      'OP_5' 'OPEN' 'ORAT' 20000  4* 1000 /
+/
+
+DATES             -- 6
+ 15  SEP 2014 /
+/
+WCONPROD
+      'OP_3' 'SHUT' 'ORAT' 20000  4* 1000 /
+/
+
+DATES             -- 7
+ 9  OCT 2014 /
+/
+WELSPECS
+      'OP_6'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  /
+/
+COMPDAT
+      'OP_6'  9  9   3  9 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 /
+/
+WCONPROD
+      'OP_6' 'OPEN' 'ORAT' 20000  4* 1000 /
+/
+TSTEP            -- 8
+10 /
+)~" };
+
+        return Opm::Parser{}.parseString(input);
+    }
+
+
+
+} // namespace
+
+struct SimulationCase
+{
+    explicit SimulationCase(const Opm::Deck& deck)
+        : es   { deck }
+        , grid { deck }
+        , sched{ deck, es }
+    {}
+
+    // Order requirement: 'es' must be declared/initialised before 'sched'.
+    Opm::EclipseState es;
+    Opm::EclipseGrid  grid;
+    Opm::Schedule     sched;
+};
+
+// =====================================================================
+BOOST_AUTO_TEST_CASE(group_test) {
+    const auto simCase = SimulationCase{first_sim()};
+    const auto& units = simCase.es.getUnits();
+    // Report Step 2: 2011-01-20 --> 2013-06-15
+    const auto rptStep = std::size_t{2};
+    const auto sim_step = rptStep - 1;
+    Opm::SummaryState sumState(std::chrono::system_clock::now());
+
+    const auto ih = Opm::RestartIO::Helpers::createInteHead(simCase.es,
+                                                            simCase.grid,
+                                                            simCase.sched,
+                                                            0,
+                                                            sim_step,
+                                                            sim_step);
+
+    const auto lh = Opm::RestartIO::Helpers::createLogiHead(simCase.es);
+
+    const auto dh = Opm::RestartIO::Helpers::createDoubHead(simCase.es,
+                                                            simCase.sched,
+                                                            sim_step,
+                                                            0, 0);
+
+    auto groupData = Opm::RestartIO::Helpers::AggregateGroupData(ih);
+    groupData.captureDeclaredGroupData(simCase.sched, units, sim_step, sumState, ih);
+
+    const auto& igrp = groupData.getIGroup();
+    const auto& sgrp = groupData.getSGroup();
+    const auto& xgrp = groupData.getXGroup();
+    const auto& zgrp8 = groupData.getZGroup();
+
+    std::vector<std::string> zgrp;
+    for (const auto& s8: zgrp8)
+        zgrp.push_back(s8.c_str());
+
+    Opm::RestartIO::RstHeader header(ih,lh,dh);
+    for (int ig=0; ig < header.ngroup; ig++) {
+        std::size_t zgrp_offset = ig * header.nzgrpz;
+        std::size_t igrp_offset = ig * header.nigrpz;
+        std::size_t sgrp_offset = ig * header.nsgrpz;
+        std::size_t xgrp_offset = ig * header.nxgrpz;
+
+        Opm::RestartIO::RstGroup group(zgrp.data() + zgrp_offset,
+                                       igrp.data() + igrp_offset,
+                                       sgrp.data() + sgrp_offset,
+                                       xgrp.data() + xgrp_offset);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(State_test) {
+    const auto simCase = SimulationCase{first_sim()};
+    const auto& units = simCase.es.getUnits();
+    // Report Step 2: 2011-01-20 --> 2013-06-15
+    const auto rptStep = std::size_t{2};
+    const auto sim_step = rptStep - 1;
+    Opm::SummaryState sumState(std::chrono::system_clock::now());
+
+    const auto ih = Opm::RestartIO::Helpers::createInteHead(simCase.es,
+                                                            simCase.grid,
+                                                            simCase.sched,
+                                                            0,
+                                                            sim_step,
+                                                            sim_step);
+
+    const auto lh = Opm::RestartIO::Helpers::createLogiHead(simCase.es);
+
+    const auto dh = Opm::RestartIO::Helpers::createDoubHead(simCase.es,
+                                                            simCase.sched,
+                                                            sim_step,
+                                                            0, 0);
+
+    auto wellData = Opm::RestartIO::Helpers::AggregateWellData(ih);
+    wellData.captureDeclaredWellData(simCase.sched, units, sim_step, sumState, ih);
+    wellData.captureDynamicWellData(simCase.sched, sim_step, {} , sumState);
+
+    auto connectionData = Opm::RestartIO::Helpers::AggregateConnectionData(ih);
+    connectionData.captureDeclaredConnData(simCase.sched, simCase.grid, units, {} , sim_step);
+
+    auto groupData = Opm::RestartIO::Helpers::AggregateGroupData(ih);
+    groupData.captureDeclaredGroupData(simCase.sched, units, sim_step, sumState, ih);
+
+    const auto& iwel = wellData.getIWell();
+    const auto& swel = wellData.getSWell();
+    const auto& xwel = wellData.getXWell();
+    const auto& zwel8 = wellData.getZWell();
+
+    const auto& icon = connectionData.getIConn();
+    const auto& scon = connectionData.getSConn();
+    const auto& xcon = connectionData.getXConn();
+
+    const auto& zgrp8 = groupData.getZGroup();
+    const auto& igrp = groupData.getIGroup();
+    const auto& sgrp = groupData.getSGroup();
+    const auto& xgrp = groupData.getXGroup();
+
+    std::vector<std::string> zwel;
+    for (const auto& s8: zwel8)
+        zwel.push_back(s8.c_str());
+
+    std::vector<std::string> zgrp;
+    for (const auto& s8: zgrp8)
+        zgrp.push_back(s8.c_str());
+
+    Opm::RestartIO::RstState state(ih, lh, dh,
+                                   zgrp, igrp, sgrp, xgrp,
+                                   zwel, iwel, swel, xwel,
+                                   icon, scon, xcon);
+}