Index: Ringtoets/Piping/src/Ringtoets.Piping.Data/GeneralPipingInput.cs
===================================================================
diff -u -r69f931d615d8cd933b51ce0b087c45db08a19a16 -r62449d45d8f5103efc40871efe09d8c6653e7c42
--- Ringtoets/Piping/src/Ringtoets.Piping.Data/GeneralPipingInput.cs	(.../GeneralPipingInput.cs)	(revision 69f931d615d8cd933b51ce0b087c45db08a19a16)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Data/GeneralPipingInput.cs	(.../GeneralPipingInput.cs)	(revision 62449d45d8f5103efc40871efe09d8c6653e7c42)
@@ -51,7 +51,7 @@
         /// Gets the volumetric weight of water.
         /// [kN/m³]
         /// </summary>
-        public double WaterVolumetricWeight { get; private set; }
+        public double WaterVolumetricWeight { get; set; }
 
         #endregion
 
Index: Ringtoets/Piping/src/Ringtoets.Piping.Forms/PropertyClasses/PipingFailureMechanismContextProperties.cs
===================================================================
diff -u -r92577a6b118858bdcfd7d46693dbd03933181837 -r62449d45d8f5103efc40871efe09d8c6653e7c42
--- Ringtoets/Piping/src/Ringtoets.Piping.Forms/PropertyClasses/PipingFailureMechanismContextProperties.cs	(.../PipingFailureMechanismContextProperties.cs)	(revision 92577a6b118858bdcfd7d46693dbd03933181837)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Forms/PropertyClasses/PipingFailureMechanismContextProperties.cs	(.../PipingFailureMechanismContextProperties.cs)	(revision 62449d45d8f5103efc40871efe09d8c6653e7c42)
@@ -85,6 +85,11 @@
             {
                 return data.WrappedData.GeneralInput.WaterVolumetricWeight;
             }
+            set
+            {
+                data.WrappedData.GeneralInput.WaterVolumetricWeight = value;
+                data.WrappedData.NotifyObservers();
+            }
         }
 
         #endregion
Index: Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/PropertyClasses/PipingFailureMechanismContextPropertiesTest.cs
===================================================================
diff -u -rad8a40bb3533cc041b82e9803fa1eaaf7410e5e0 -r62449d45d8f5103efc40871efe09d8c6653e7c42
--- Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/PropertyClasses/PipingFailureMechanismContextPropertiesTest.cs	(.../PipingFailureMechanismContextPropertiesTest.cs)	(revision ad8a40bb3533cc041b82e9803fa1eaaf7410e5e0)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/PropertyClasses/PipingFailureMechanismContextPropertiesTest.cs	(.../PipingFailureMechanismContextPropertiesTest.cs)	(revision 62449d45d8f5103efc40871efe09d8c6653e7c42)
@@ -126,7 +126,7 @@
 
             PropertyDescriptor volumicWeightOfWaterProperty = dynamicProperties[2];
             Assert.IsNotNull(volumicWeightOfWaterProperty);
-            Assert.IsTrue(volumicWeightOfWaterProperty.IsReadOnly);
+            Assert.IsFalse(volumicWeightOfWaterProperty.IsReadOnly);
             Assert.AreEqual(generalCategory, volumicWeightOfWaterProperty.Category);
             Assert.AreEqual("Volumiek gewicht van water [kN/m³]", volumicWeightOfWaterProperty.DisplayName);
             Assert.AreEqual("Volumiek gewicht van water.", volumicWeightOfWaterProperty.Description);
@@ -275,5 +275,32 @@
             Assert.AreEqual(value, failureMechanism.PipingProbabilityAssessmentInput.A);
             mocks.VerifyAll();
         }
+
+        [Test]
+        public void WaterVolumetricWeight_SetValue_SetsValueAndUpdatesObservers()
+        {
+            // Setup
+            var mocks = new MockRepository();
+            var observerMock = mocks.StrictMock<IObserver>();
+            observerMock.Expect(o => o.UpdateObserver());
+            mocks.ReplayAll();
+
+            var failureMechanism = new PipingFailureMechanism();
+            var properties = new PipingFailureMechanismContextProperties
+            {
+                Data = new PipingFailureMechanismContext(failureMechanism, new MockRepository().StrictMock<IAssessmentSection>())
+            };
+
+            failureMechanism.Attach(observerMock);
+
+            const double newValue = 5;
+
+            // Call            
+            properties.WaterVolumetricWeight = newValue;
+
+            // Assert
+            Assert.AreEqual(newValue, failureMechanism.GeneralInput.WaterVolumetricWeight);
+            mocks.VerifyAll();
+        }
     }
 }
\ No newline at end of file