diff --git a/ebos/equil/initstateequil.hh b/ebos/equil/initstateequil.hh
index e7d03b6ef..6c200ac55 100644
--- a/ebos/equil/initstateequil.hh
+++ b/ebos/equil/initstateequil.hh
@@ -1713,7 +1713,7 @@ public:
 
         // Compute pressures, saturations, rs and rv factors.
         const auto& comm = gridView.comm();
-        calcPressSatRsRv(eqlmap, rec, materialLawManager, gridView, num_aquifers, comm, grav);
+        calcPressSatRsRv(eqlmap, rec, materialLawManager, num_aquifers, comm, grav);
 
         // Modify oil pressure in no-oil regions so that the pressures of present phases can
         // be recovered from the oil pressure and capillary relations.
@@ -1824,9 +1824,8 @@ private:
 
     template <class RMap, class MaterialLawManager, class Comm>
     void calcPressSatRsRv(const RMap& reg,
-                          const std::vector< Opm::EquilRecord >& rec,
+                          const std::vector<Opm::EquilRecord>& rec,
                           MaterialLawManager& materialLawManager,
-                          const GridView& gridView,
                           const NumericalAquifers& aquifer,
                           const Comm& comm,
                           const double grav)
@@ -1864,7 +1863,7 @@ private:
             const auto acc = eqreg.equilibrationAccuracy();
             if (acc == 0) {
                 // Centre-point method
-                this->equilibrateCellCentres(cells, eqreg, ptable, gridView, aquifer, psat);
+                this->equilibrateCellCentres(cells, eqreg, ptable, aquifer, psat);
             }
             else if (acc < 0) {
                 // Horizontal subdivision
@@ -1925,12 +1924,11 @@ private:
     }
 
     template <class CellRange, class PressTable, class PhaseSat>
-    void equilibrateCellCentres(const CellRange&  cells,
-                                const EquilReg&   eqreg,
-                                const PressTable& ptable,
-                                const GridView& gridView,
+    void equilibrateCellCentres(const CellRange&         cells,
+                                const EquilReg&          eqreg,
+                                const PressTable&        ptable,
                                 const NumericalAquifers& aquifer,
-                                PhaseSat&         psat)
+                                PhaseSat&                psat)
     {
         using CellPos = typename PhaseSat::Position;
         using CellID  = std::remove_cv_t<std::remove_reference_t<
diff --git a/opm/simulators/aquifers/AquiferNumerical.hpp b/opm/simulators/aquifers/AquiferNumerical.hpp
index 1ff524923..9782ea86c 100644
--- a/opm/simulators/aquifers/AquiferNumerical.hpp
+++ b/opm/simulators/aquifers/AquiferNumerical.hpp
@@ -64,12 +64,16 @@ public:
         for (size_t idx = 0; idx < aquifer.numCells(); ++idx) {
             const auto& cell = *(aquifer.getCellPrt(idx));
             const int global_idx = cell.global_index;
-            const int cell_idx = cartesian_to_compressed.at(global_idx);
-            this->cell_to_aquifer_cell_idx_[cell_idx] = idx;
+            const auto search = cartesian_to_compressed.find(global_idx);
+            // Due to parallelisation, the cell might not exist in the current process
+            if (search != cartesian_to_compressed.end()) {
+                const int cell_idx = cartesian_to_compressed.at(global_idx);
+                this->cell_to_aquifer_cell_idx_[cell_idx] = idx;
+            }
         }
     }
 
-    void initFromRestart(const std::vector<data::AquiferData>& aquiferSoln)
+    void initFromRestart([[maybe_unused]]const std::vector<data::AquiferData>& aquiferSoln)
     {
         // NOT handling Restart for now
     }
@@ -148,6 +152,9 @@ private:
             sum_watervolume += water_volume;
         }
 
+        const auto& comm = this->ebos_simulator_.vanguard().grid().comm();
+        comm.sum(&sum_pressure_watervolume, 1);
+        comm.sum(&sum_watervolume, 1);
         return sum_pressure_watervolume / sum_watervolume;
     }
 
@@ -208,6 +215,8 @@ private:
             break;
         }
 
+        const auto& comm = this->ebos_simulator_.vanguard().grid().comm();
+        comm.sum(&aquifer_flux, 1);
         return aquifer_flux;
     }
 };