diff --git a/opm/simulators/aquifers/AquiferFetkovich.hpp b/opm/simulators/aquifers/AquiferFetkovich.hpp
index ac53e8ab6..68bb7e7be 100644
--- a/opm/simulators/aquifers/AquiferFetkovich.hpp
+++ b/opm/simulators/aquifers/AquiferFetkovich.hpp
@@ -107,6 +107,7 @@ protected:
         }
 
         this->aquifer_pressure_ = xaq.pressure;
+        this->rhow_ = this->aqufetp_data_.waterDensity();
     }
 
     inline Eval dpai(int idx)