Index: Ringtoets/Revetment/src/Ringtoets.Revetment.Data/WaveConditionsInput.cs
===================================================================
diff -u -rea8531ddaa6352d92963b54023041fde69af5c49 -rb762914ea1a584bb69a286d389a8a6a83d171769
--- Ringtoets/Revetment/src/Ringtoets.Revetment.Data/WaveConditionsInput.cs	(.../WaveConditionsInput.cs)	(revision ea8531ddaa6352d92963b54023041fde69af5c49)
+++ Ringtoets/Revetment/src/Ringtoets.Revetment.Data/WaveConditionsInput.cs	(.../WaveConditionsInput.cs)	(revision b762914ea1a584bb69a286d389a8a6a83d171769)
@@ -217,15 +217,19 @@
 
         private static void ValidateRevetmentLevels(RoundedDouble lowerRevetmentLevelValue, RoundedDouble upperRevetmentLevelValue)
         {
-            if (lowerRevetmentLevelValue >= upperRevetmentLevelValue)
+            if (!double.IsNaN(lowerRevetmentLevelValue)
+                && !double.IsNaN(upperRevetmentLevelValue)
+                && lowerRevetmentLevelValue >= upperRevetmentLevelValue)
             {
                 throw new ArgumentOutOfRangeException(null, Resources.WaveConditionsInput_ValidateRevetmentLevels_Upper_revetment_level_must_be_above_lower_revetment_level);
             }
         }
 
         private static void ValidateCalculatorSeriesBoundaries(RoundedDouble lowerBoundary, RoundedDouble upperBoundary)
         {
-            if (lowerBoundary >= upperBoundary)
+            if (!double.IsNaN(lowerBoundary)
+                && !double.IsNaN(upperBoundary)
+                && lowerBoundary >= upperBoundary)
             {
                 throw new ArgumentOutOfRangeException(null, Resources.WaveConditionsInput_ValidateCalculatorSeriesBoundaries_Calculator_series_upperboundary_must_be_above_lowerboundary);
             }
Index: Ringtoets/Revetment/test/Ringtoets.Revetment.Data.Test/WaveConditionsInputTest.cs
===================================================================
diff -u -rea8531ddaa6352d92963b54023041fde69af5c49 -rb762914ea1a584bb69a286d389a8a6a83d171769
--- Ringtoets/Revetment/test/Ringtoets.Revetment.Data.Test/WaveConditionsInputTest.cs	(.../WaveConditionsInputTest.cs)	(revision ea8531ddaa6352d92963b54023041fde69af5c49)
+++ Ringtoets/Revetment/test/Ringtoets.Revetment.Data.Test/WaveConditionsInputTest.cs	(.../WaveConditionsInputTest.cs)	(revision b762914ea1a584bb69a286d389a8a6a83d171769)
@@ -246,10 +246,7 @@
         public void LowerRevetmentLevel_SetNewValue_ValueIsRounded()
         {
             // Setup
-            var input = new WaveConditionsInput
-            {
-                UpperRevetmentLevel = (RoundedDouble) 4.0
-            };
+            var input = new WaveConditionsInput();
 
             int originalNumberOfDecimalPlaces = input.LowerRevetmentLevel.NumberOfDecimalPlaces;
 
@@ -298,10 +295,7 @@
         public void LowerBoundaryCalculatorSeries_SetNewValue_ValueIsRounded()
         {
             // Setup
-            var input = new WaveConditionsInput
-            {
-                UpperBoundaryCalculatorSeries = (RoundedDouble) 3.0
-            };
+            var input = new WaveConditionsInput();
 
             int originalNumberOfDecimalPlaces = input.LowerBoundaryCalculatorSeries.NumberOfDecimalPlaces;
 
@@ -342,7 +336,6 @@
             // Setup
             var input = new WaveConditionsInput
             {
-                UpperBoundaryCalculatorSeries = (RoundedDouble) 4.0,
                 LowerBoundaryCalculatorSeries = (RoundedDouble) 3.0
             };