Index: Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Service/GrassCoverErosionOutwardsWaveConditionsCalculationService.cs
===================================================================
diff -u -rb4b93f81c63d098edfd9e50ce1c94e37903e52f6 -rc96deb3a33a6779c640b20b1c866bb93530fad02
--- Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Service/GrassCoverErosionOutwardsWaveConditionsCalculationService.cs	(.../GrassCoverErosionOutwardsWaveConditionsCalculationService.cs)	(revision b4b93f81c63d098edfd9e50ce1c94e37903e52f6)
+++ Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Service/GrassCoverErosionOutwardsWaveConditionsCalculationService.cs	(.../GrassCoverErosionOutwardsWaveConditionsCalculationService.cs)	(revision c96deb3a33a6779c640b20b1c866bb93530fad02)
@@ -44,22 +44,26 @@
         /// Performs validation over the input parameters. Error and status information is logged during the execution of the operation.
         /// </summary>
         /// <param name="calculation">The <see cref="GrassCoverErosionOutwardsWaveConditionsCalculation"/> for which to validate the values.</param>
+        /// <param name="normativeAssessmentLevel">The normative assessment level to use for determining water levels.</param>
         /// <param name="hydraulicBoundaryDatabaseFilePath">The file path of the hydraulic boundary database file which to validate.</param>
         /// <param name="preprocessorDirectory">The preprocessor directory to validate.</param>
         /// <returns><c>true</c> if there were no validation errors; <c>false</c> otherwise.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="calculation"/> is <c>null</c>.</exception>
-        public static bool Validate(GrassCoverErosionOutwardsWaveConditionsCalculation calculation, string hydraulicBoundaryDatabaseFilePath, string preprocessorDirectory)
+        public static bool Validate(GrassCoverErosionOutwardsWaveConditionsCalculation calculation,
+                                    RoundedDouble normativeAssessmentLevel,
+                                    string hydraulicBoundaryDatabaseFilePath,
+                                    string preprocessorDirectory)
         {
             if (calculation == null)
             {
                 throw new ArgumentNullException(nameof(calculation));
             }
 
-            return ValidateWaveConditionsInput(
-                calculation.InputParameters,
-                hydraulicBoundaryDatabaseFilePath,
-                preprocessorDirectory,
-                Resources.GrassCoverErosionOutwardsWaveConditionsCalculationService_LogMessage_DesignWaterLevel_name);
+            return ValidateWaveConditionsInput(calculation.InputParameters,
+                                               normativeAssessmentLevel,
+                                               hydraulicBoundaryDatabaseFilePath,
+                                               preprocessorDirectory,
+                                               Resources.GrassCoverErosionOutwardsWaveConditionsCalculationService_LogMessage_DesignWaterLevel_name);
         }
 
         /// <summary>
@@ -102,10 +106,12 @@
             {
                 throw new ArgumentNullException(nameof(calculation));
             }
+
             if (failureMechanism == null)
             {
                 throw new ArgumentNullException(nameof(failureMechanism));
             }
+
             if (assessmentSection == null)
             {
                 throw new ArgumentNullException(nameof(assessmentSection));