diff --git a/opm/simulators/wells/GroupState.cpp b/opm/simulators/wells/GroupState.cpp
index 702a08589..0102b0b40 100644
--- a/opm/simulators/wells/GroupState.cpp
+++ b/opm/simulators/wells/GroupState.cpp
@@ -268,70 +268,4 @@ bool GroupState::has_gpmaint_target(const std::string& gname) const {
     return (this->m_gpmaint_target.count(gname) > 0);
 }
 
-//-------------------------------------------------------------------------
-
-namespace {
-
-template <typename T>
-void dump_vector(Json::JsonObject& root, const std::string& key, const std::vector<T>& data) {
-    auto data_obj = root.add_array(key);
-    for (const auto& rate : data)
-        data_obj.add(rate);
-}
-
-
-template <typename T>
-void dump_groupmap(Json::JsonObject& root, const std::string& key, const std::map<std::string, std::vector<T>>& group_data) {
-    auto map_obj = root.add_object(key);
-    for (const auto& [gname, data] : group_data)
-        dump_vector(map_obj, gname, data);
-}
-
-
-template <typename T>
-void dump_groupmap(Json::JsonObject& root, const std::string& key, const std::map<std::string, T>& group_data) {
-    auto map_obj = root.add_object(key);
-    for (const auto& [gname, value] : group_data)
-        map_obj.add_item(gname, value);
-}
-
-}
-
-std::string GroupState::dump() const
-{
-    Json::JsonObject root;
-    dump_groupmap(root, "production_rates", this->m_production_rates);
-    dump_groupmap(root, "prod_red_rates", this->prod_red_rates);
-    dump_groupmap(root, "inj_red_rates", this->inj_red_rates);
-    dump_groupmap(root, "inj_resv_rates", this->inj_resv_rates);
-    dump_groupmap(root, "inj_rein_rates", this->inj_rein_rates);
-    dump_groupmap(root, "vrep_rate", this->inj_vrep_rate);
-    dump_groupmap(root, "grat_sales_target", this->m_grat_sales_target);
-    {
-        std::map<std::string, int> int_controls;
-        for (const auto& [gname, control] : this->production_controls)
-            int_controls.insert({gname, static_cast<int>(control)});
-        dump_groupmap(root, "production_controls", int_controls);
-    }
-    {
-        std::map<std::string, std::vector<std::pair<Opm::Phase, Group::InjectionCMode>>> inj_cntrl;
-        for (const auto& [phase_name, cmode] : this->injection_controls) {
-            const auto& [phase, gname] = phase_name;
-            inj_cntrl[gname].emplace_back(phase, cmode);
-        }
-
-        auto map_obj = root.add_object("injection_controls");
-        for (const auto& [gname, phase_cmode] : inj_cntrl) {
-            auto group_array = map_obj.add_array(gname);
-            for (const auto& [phase, cmode] : phase_cmode) {
-                auto control_pair = group_array.add_array();
-                control_pair.add(static_cast<int>(phase));
-                control_pair.add(static_cast<int>(cmode));
-            }
-        }
-    }
-    return root.to_string();
-}
-
-
 }
diff --git a/opm/simulators/wells/GroupState.hpp b/opm/simulators/wells/GroupState.hpp
index 98ee3994f..674ddf4fd 100644
--- a/opm/simulators/wells/GroupState.hpp
+++ b/opm/simulators/wells/GroupState.hpp
@@ -159,8 +159,6 @@ public:
             throw std::logic_error("Internal size mismatch when distributing groupData");
     }
 
-    std::string dump() const;
-
 
 private:
     std::size_t num_phases;
diff --git a/tests/test_GroupState.cpp b/tests/test_GroupState.cpp
index f549d6b8a..2538bbca4 100644
--- a/tests/test_GroupState.cpp
+++ b/tests/test_GroupState.cpp
@@ -70,15 +70,3 @@ BOOST_AUTO_TEST_CASE(GroupStateCreate) {
 }
 
 
-BOOST_AUTO_TEST_CASE(GroupStateDump) {
-    std::size_t num_phases{3};
-    GroupState gs(num_phases);
-    std::vector<double> rates{0,1,2};
-    gs.update_production_rates("AGROUP", rates);
-    gs.update_injection_rein_rates("CGROUP", rates);
-    gs.injection_control("AGROUP", Phase::WATER, Group::InjectionCMode::RATE);
-    gs.injection_control("AGROUP", Phase::GAS, Group::InjectionCMode::RATE);
-
-    auto json_string = gs.dump();
-    Json::JsonObject json_gs(json_string);
-}