Index: Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.CalculatedInput/WaternetCalculationService.cs
===================================================================
diff -u -re77815b31b213789da306754de0867d6cb2de105 -rde2931de5e3ccab7c7d127723b6a3be373518131
--- Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.CalculatedInput/WaternetCalculationService.cs	(.../WaternetCalculationService.cs)	(revision e77815b31b213789da306754de0867d6cb2de105)
+++ Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.CalculatedInput/WaternetCalculationService.cs	(.../WaternetCalculationService.cs)	(revision de2931de5e3ccab7c7d127723b6a3be373518131)
@@ -49,7 +49,8 @@
         /// could not be calculated.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="input"/>
         /// is <c>null</c>.</exception>
-        public static MacroStabilityInwardsWaternet CalculateExtreme(IMacroStabilityInwardsWaternetInput input, RoundedDouble assessmentLevel)
+        public static MacroStabilityInwardsWaternet CalculateExtreme(IMacroStabilityInwardsWaternetInput input,
+                                                                     RoundedDouble assessmentLevel)
         {
             if (input == null)
             {
Index: Ringtoets/MacroStabilityInwards/test/Ringtoets.MacroStabilityInwards.CalculatedInput.Test/WaternetCalculationServiceTest.cs
===================================================================
diff -u -r5c7faf8283e49113a2c7b9e17086148a99f13d2e -rde2931de5e3ccab7c7d127723b6a3be373518131
--- Ringtoets/MacroStabilityInwards/test/Ringtoets.MacroStabilityInwards.CalculatedInput.Test/WaternetCalculationServiceTest.cs	(.../WaternetCalculationServiceTest.cs)	(revision 5c7faf8283e49113a2c7b9e17086148a99f13d2e)
+++ Ringtoets/MacroStabilityInwards/test/Ringtoets.MacroStabilityInwards.CalculatedInput.Test/WaternetCalculationServiceTest.cs	(.../WaternetCalculationServiceTest.cs)	(revision de2931de5e3ccab7c7d127723b6a3be373518131)
@@ -20,6 +20,8 @@
 // All rights reserved.
 
 using System;
+using Core.Common.Base.Data;
+using Core.Common.TestUtil;
 using NUnit.Framework;
 using Ringtoets.MacroStabilityInwards.CalculatedInput.TestUtil;
 using Ringtoets.MacroStabilityInwards.Data;
@@ -47,7 +49,7 @@
         public void CalculateExtreme_InputNull_ThrowsArgumentNullException()
         {
             // Call
-            TestDelegate call = () => WaternetCalculationService.CalculateExtreme(null);
+            TestDelegate call = () => WaternetCalculationService.CalculateExtreme(null, RoundedDouble.NaN);
 
             // Assert
             var exception = Assert.Throws<ArgumentNullException>(call);
@@ -58,12 +60,13 @@
         public void CalculateExtreme_WithInput_SetsInputOnCalculator()
         {
             // Setup
+            RoundedDouble assessmentLevel = new Random(21).NextRoundedDouble();
             MacroStabilityInwardsInput input = testCalculation.InputParameters;
 
             using (new MacroStabilityInwardsCalculatorFactoryConfig())
             {
                 // Call
-                WaternetCalculationService.CalculateExtreme(input);
+                WaternetCalculationService.CalculateExtreme(input, assessmentLevel);
 
                 // Assert
                 var factory = (TestMacroStabilityInwardsCalculatorFactory) MacroStabilityInwardsCalculatorFactory.Instance;
@@ -72,7 +75,7 @@
                 CalculatorInputAssert.AssertPhreaticLineOffsets(input.LocationInputExtreme, actualInput.PhreaticLineOffsets);
                 Assert.AreEqual(input.LocationInputExtreme.WaterLevelPolder, actualInput.WaterLevelPolder);
                 Assert.AreEqual(input.LocationInputExtreme.PenetrationLength, actualInput.PenetrationLength);
-                Assert.AreEqual(input.AssessmentLevel, actualInput.AssessmentLevel);
+                Assert.AreEqual(assessmentLevel, actualInput.AssessmentLevel);
 
                 AssertGenericInput(input, actualInput);
             }
@@ -87,7 +90,7 @@
                 var calculatorFactory = (TestMacroStabilityInwardsCalculatorFactory) MacroStabilityInwardsCalculatorFactory.Instance;
 
                 // Call
-                MacroStabilityInwardsWaternet output = WaternetCalculationService.CalculateExtreme(testCalculation.InputParameters);
+                MacroStabilityInwardsWaternet output = WaternetCalculationService.CalculateExtreme(testCalculation.InputParameters, RoundedDouble.NaN);
 
                 // Assert
                 CalculatorOutputAssert.AssertWaternet(calculatorFactory.LastCreatedWaternetCalculator.Output, output);
@@ -104,7 +107,7 @@
                 calculatorFactory.LastCreatedWaternetCalculator.ThrowExceptionOnCalculate = true;
 
                 // Call
-                MacroStabilityInwardsWaternet output = WaternetCalculationService.CalculateExtreme(testCalculation.InputParameters);
+                MacroStabilityInwardsWaternet output = WaternetCalculationService.CalculateExtreme(testCalculation.InputParameters, RoundedDouble.NaN);
 
                 // Assert
                 Assert.IsNotNull(output);