Index: Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Service/MacroStabilityInwardsCalculationService.cs
===================================================================
diff -u -r8d246ac6328e6e649ff6e78dfe3fac210d789ba0 -r0da7a76905c549ccda8339fc255e1efa156807f4
--- Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Service/MacroStabilityInwardsCalculationService.cs	(.../MacroStabilityInwardsCalculationService.cs)	(revision 8d246ac6328e6e649ff6e78dfe3fac210d789ba0)
+++ Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Service/MacroStabilityInwardsCalculationService.cs	(.../MacroStabilityInwardsCalculationService.cs)	(revision 0da7a76905c549ccda8339fc255e1efa156807f4)
@@ -21,6 +21,7 @@
 
 using System;
 using System.Linq;
+using Core.Common.Base.Data;
 using Ringtoets.Common.Service;
 using Ringtoets.MacroStabilityInwards.CalculatedInput.Converters;
 using Ringtoets.MacroStabilityInwards.Data;
@@ -46,9 +47,10 @@
         /// the execution of the operation.
         /// </summary>
         /// <param name="calculation">The <see cref="MacroStabilityInwardsCalculation"/> for which to validate the values.</param>
+        /// <param name="normativeAssessmentLevel">The normative assessment level to use in case no manual assessment level is provided.</param>
         /// <returns><c>false</c> if <paramref name="calculation"/> contains validation errors; <c>true</c> otherwise.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="calculation"/> is <c>null</c>.</exception>
-        public static bool Validate(MacroStabilityInwardsCalculation calculation)
+        public static bool Validate(MacroStabilityInwardsCalculation calculation, RoundedDouble normativeAssessmentLevel)
         {
             if (calculation == null)
             {
@@ -57,7 +59,7 @@
 
             CalculationServiceHelper.LogValidationBegin();
 
-            string[] inputValidationResults = MacroStabilityInwardsInputValidator.Validate(calculation.InputParameters).ToArray();
+            string[] inputValidationResults = MacroStabilityInwardsInputValidator.Validate(calculation.InputParameters, normativeAssessmentLevel).ToArray();
 
             if (inputValidationResults.Length > 0)
             {
@@ -66,7 +68,7 @@
                 return false;
             }
 
-            UpliftVanCalculatorInput upliftVanCalculatorInput = CreateInputFromData(calculation.InputParameters);
+            UpliftVanCalculatorInput upliftVanCalculatorInput = CreateInputFromData(calculation.InputParameters, normativeAssessmentLevel);
             IUpliftVanCalculator calculator = MacroStabilityInwardsCalculatorFactory.Instance.CreateUpliftVanCalculator(upliftVanCalculatorInput, MacroStabilityInwardsKernelWrapperFactory.Instance);
 
             UpliftVanKernelMessage[] kernelMessages;
@@ -96,10 +98,11 @@
         /// the execution of the operation.
         /// </summary>
         /// <param name="calculation">The <see cref="MacroStabilityInwardsCalculation"/> to base the input for the calculation upon.</param>
+        /// <param name="normativeAssessmentLevel">The normative assessment level to use in case no manual assessment level is provided.</param>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="calculation"/> is <c>null</c>.</exception>
         /// <remarks>Consider calling <see cref="Validate"/> first to see if calculation is possible.</remarks>
         /// <exception cref="UpliftVanCalculatorException">Thrown when an error occurred during the calculation.</exception>
-        public static void Calculate(MacroStabilityInwardsCalculation calculation)
+        public static void Calculate(MacroStabilityInwardsCalculation calculation, RoundedDouble normativeAssessmentLevel)
         {
             if (calculation == null)
             {
@@ -111,7 +114,7 @@
             try
             {
                 IUpliftVanCalculator calculator = MacroStabilityInwardsCalculatorFactory.Instance.CreateUpliftVanCalculator(
-                    CreateInputFromData(calculation.InputParameters),
+                    CreateInputFromData(calculation.InputParameters, normativeAssessmentLevel),
                     MacroStabilityInwardsKernelWrapperFactory.Instance);
                 UpliftVanCalculatorResult macroStabilityInwardsResult = calculator.Calculate();
 
@@ -157,14 +160,18 @@
             }
         }
 
-        private static UpliftVanCalculatorInput CreateInputFromData(MacroStabilityInwardsInput inputParameters)
+        private static UpliftVanCalculatorInput CreateInputFromData(MacroStabilityInwardsInput inputParameters, RoundedDouble normativeAssessmentLevel)
         {
+            RoundedDouble effectiveAssessmentLevel = inputParameters.UseAssessmentLevelManualInput
+                                                         ? inputParameters.AssessmentLevel
+                                                         : normativeAssessmentLevel;
+
             return new UpliftVanCalculatorInput(
                 new UpliftVanCalculatorInput.ConstructionProperties
                 {
                     WaternetCreationMode = WaternetCreationMode.CreateWaternet,
                     PlLineCreationMethod = PlLineCreationMethod.RingtoetsWti2017,
-                    AssessmentLevel = inputParameters.AssessmentLevel,
+                    AssessmentLevel = effectiveAssessmentLevel,
                     LandwardDirection = LandwardDirection.PositiveX,
                     SurfaceLine = inputParameters.SurfaceLine,
                     SoilProfile = SoilProfileConverter.Convert(inputParameters.SoilProfileUnderSurfaceLine),
Index: Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Service/MacroStabilityInwardsInputValidator.cs
===================================================================
diff -u -r8d246ac6328e6e649ff6e78dfe3fac210d789ba0 -r0da7a76905c549ccda8339fc255e1efa156807f4
--- Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Service/MacroStabilityInwardsInputValidator.cs	(.../MacroStabilityInwardsInputValidator.cs)	(revision 8d246ac6328e6e649ff6e78dfe3fac210d789ba0)
+++ Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Service/MacroStabilityInwardsInputValidator.cs	(.../MacroStabilityInwardsInputValidator.cs)	(revision 0da7a76905c549ccda8339fc255e1efa156807f4)
@@ -45,8 +45,9 @@
         /// </summary>
         /// <param name="inputParameters">The <see cref="MacroStabilityInwardsInput"/> for which to validate the values.</param>
         /// <returns>Validation errors, if any.</returns>
+        /// <param name="normativeAssessmentLevel">The normative assessment level to use in case no manual assessment level is provided.</param>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="inputParameters"/> is <c>null</c>.</exception>
-        public static IEnumerable<string> Validate(MacroStabilityInwardsInput inputParameters)
+        public static IEnumerable<string> Validate(MacroStabilityInwardsInput inputParameters, RoundedDouble normativeAssessmentLevel)
         {
             if (inputParameters == null)
             {
@@ -55,7 +56,7 @@
 
             var validationResults = new List<string>();
 
-            validationResults.AddRange(ValidateHydraulics(inputParameters));
+            validationResults.AddRange(ValidateHydraulics(inputParameters, normativeAssessmentLevel));
 
             IEnumerable<string> coreValidationError = ValidateCoreSurfaceLineAndSoilProfileProperties(inputParameters).ToArray();
             validationResults.AddRange(coreValidationError);
@@ -79,6 +80,7 @@
                 {
                     yield return Resources.MacroStabilityInwardsCalculationService_ValidateInput_SoilLayerTop_must_be_larger_than_SurfaceLineTop;
                 }
+
                 yield break;
             }
 
@@ -153,6 +155,7 @@
                     return false;
                 }
             }
+
             return true;
         }
 
@@ -191,10 +194,11 @@
                     return true;
                 }
             }
+
             return false;
         }
 
-        private static IEnumerable<string> ValidateHydraulics(MacroStabilityInwardsInput inputParameters)
+        private static IEnumerable<string> ValidateHydraulics(MacroStabilityInwardsInput inputParameters, RoundedDouble normativeAssessmentLevel)
         {
             var validationResults = new List<string>();
             if (!inputParameters.UseAssessmentLevelManualInput && inputParameters.HydraulicBoundaryLocation == null)
@@ -203,13 +207,13 @@
             }
             else
             {
-                validationResults.AddRange(ValidateAssessmentLevel(inputParameters));
+                validationResults.AddRange(ValidateAssessmentLevel(inputParameters, normativeAssessmentLevel));
             }
 
             return validationResults;
         }
 
-        private static IEnumerable<string> ValidateAssessmentLevel(MacroStabilityInwardsInput inputParameters)
+        private static IEnumerable<string> ValidateAssessmentLevel(MacroStabilityInwardsInput inputParameters, RoundedDouble normativeAssessmentLevel)
         {
             var validationResult = new List<string>();
 
@@ -219,7 +223,7 @@
             }
             else
             {
-                if (double.IsNaN(inputParameters.AssessmentLevel))
+                if (double.IsNaN(normativeAssessmentLevel))
                 {
                     validationResult.Add(Resources.MacroStabilityInwardsCalculationService_ValidateInput_Cannot_determine_AssessmentLevel);
                 }
@@ -235,10 +239,12 @@
             {
                 validationResults.Add(Resources.MacroStabilityInwardsCalculationService_ValidateInput_No_SurfaceLine_selected);
             }
+
             if (inputParameters.StochasticSoilProfile == null)
             {
                 validationResults.Add(Resources.MacroStabilityInwardsCalculationService_ValidateInput_No_StochasticSoilProfile_selected);
             }
+
             return validationResults;
         }
     }