Index: Ringtoets/Revetment/src/Ringtoets.Revetment.Data/WaveConditionsInput.cs
===================================================================
diff -u -r0e74eb0d28fddcb195ebe88e8eb1164cf23dffc9 -r2b1ae71dbd5ecd83ad0fca2ea02c5d7d8219f7b9
--- Ringtoets/Revetment/src/Ringtoets.Revetment.Data/WaveConditionsInput.cs	(.../WaveConditionsInput.cs)	(revision 0e74eb0d28fddcb195ebe88e8eb1164cf23dffc9)
+++ Ringtoets/Revetment/src/Ringtoets.Revetment.Data/WaveConditionsInput.cs	(.../WaveConditionsInput.cs)	(revision 2b1ae71dbd5ecd83ad0fca2ea02c5d7d8219f7b9)
@@ -268,13 +268,18 @@
         {
             UpperBoundary = UpperWaterLevel < UpperRevetmentLevel ? UpperWaterLevel : UpperRevetmentLevel;
             LowerBoundary = LowerWaterLevel > LowerRevetmentLevel ? LowerWaterLevel : LowerRevetmentLevel;
+
+            DetermineWaterLevels();
         }
 
         private void DetermineWaterLevels()
         {
             waterLevels.Clear();
             
-            if (double.IsNaN(UpperBoundary) || double.IsNaN(LowerBoundary) || Math.Abs(LowerBoundary - UpperBoundary) < 1e-6)
+            if (double.IsNaN(UpperBoundary) || 
+                double.IsNaN(LowerBoundary) || 
+                Math.Abs(LowerBoundary - UpperBoundary) < 1e-6 ||
+                Math.Abs(StepSize) < 1e-6)
             {
                 return;
             }