Index: Ringtoets/Common/src/Ringtoets.Common.Data/AssessmentSection/AssessmentSectionExtensions.cs
===================================================================
diff -u -r175cb39b49a146149811954e3800bebfc0819e3d -raef20c08e43fb95b037791c98c8e088352061c5e
--- Ringtoets/Common/src/Ringtoets.Common.Data/AssessmentSection/AssessmentSectionExtensions.cs	(.../AssessmentSectionExtensions.cs)	(revision 175cb39b49a146149811954e3800bebfc0819e3d)
+++ Ringtoets/Common/src/Ringtoets.Common.Data/AssessmentSection/AssessmentSectionExtensions.cs	(.../AssessmentSectionExtensions.cs)	(revision aef20c08e43fb95b037791c98c8e088352061c5e)
@@ -20,7 +20,9 @@
 // All rights reserved.
 
 using System;
+using System.Collections.Generic;
 using System.ComponentModel;
+using System.Linq;
 using Core.Common.Base.Data;
 using Ringtoets.Common.Data.Contribution;
 using Ringtoets.Common.Data.Hydraulics;
@@ -33,14 +35,14 @@
     public static class AssessmentSectionExtensions
     {
         /// <summary>
-        /// Gets the normative assessment level from a <see cref="HydraulicBoundaryLocation"/>.
+        /// Gets the normative assessment level for a <see cref="HydraulicBoundaryLocation"/>.
         /// </summary>
-        /// <param name="assessmentSection">The assessment section.</param>
-        /// <param name="hydraulicBoundaryLocation">The hydraulic boundary location to get the normative
-        /// assessment level from.</param>
+        /// <param name="assessmentSection">The assessment section to get the normative assessment level from.</param>
+        /// <param name="hydraulicBoundaryLocation">The hydraulic boundary location to get the normative assessment level for.</param>
         /// <returns>The normative assessment level or <see cref="RoundedDouble.NaN"/> when:
         /// <list type="bullet">
         /// <item><paramref name="hydraulicBoundaryLocation"/> is <c>null</c>;</item>
+        /// <item><paramref name="hydraulicBoundaryLocation"/> is not part of <paramref name="assessmentSection"/>;</item>
         /// <item><paramref name="hydraulicBoundaryLocation"/> contains no corresponding calculation output.</item>
         /// </list>
         /// </returns>
@@ -50,7 +52,8 @@
         /// contains an invalid value of <see cref="NormType"/>.</exception>
         /// <exception cref="NotSupportedException">Thrown when <paramref name="assessmentSection"/>
         /// contains a valid value of <see cref="NormType"/>, but unsupported.</exception>
-        public static RoundedDouble GetNormativeAssessmentLevel(this IAssessmentSection assessmentSection, HydraulicBoundaryLocation hydraulicBoundaryLocation)
+        public static RoundedDouble GetNormativeAssessmentLevel(this IAssessmentSection assessmentSection,
+                                                                HydraulicBoundaryLocation hydraulicBoundaryLocation)
         {
             if (assessmentSection == null)
             {
@@ -66,15 +69,85 @@
                                                        typeof(NormType));
             }
 
+            IEnumerable<HydraulicBoundaryLocationCalculation> calculations;
+
             switch (normType)
             {
                 case NormType.Signaling:
-                    return hydraulicBoundaryLocation?.DesignWaterLevelCalculation2.Output?.Result ?? RoundedDouble.NaN;
+                    calculations = assessmentSection.WaterLevelCalculationsForSignalingNorm;
+                    break;
                 case NormType.LowerLimit:
-                    return hydraulicBoundaryLocation?.DesignWaterLevelCalculation3.Output?.Result ?? RoundedDouble.NaN;
+                    calculations = assessmentSection.WaterLevelCalculationsForLowerLimitNorm;
+                    break;
                 default:
                     throw new NotSupportedException();
             }
+
+            return GetAssessmentLevelFromCalculations(hydraulicBoundaryLocation, calculations);
         }
+
+        /// <summary>
+        /// Gets the assessment level for a <see cref="HydraulicBoundaryLocation"/> based on <see cref="AssessmentSectionCategoryType"/>.
+        /// </summary>
+        /// <param name="assessmentSection">The assessment section to get the assessment level from.</param>
+        /// <param name="hydraulicBoundaryLocation">The hydraulic boundary location to get the assessment level for.</param>
+        /// <param name="categoryType">The category type to use while obtaining the assessment level.</param>
+        /// <returns>The assessment level or <see cref="RoundedDouble.NaN"/> when:
+        /// <list type="bullet">
+        /// <item><paramref name="hydraulicBoundaryLocation"/> is <c>null</c>;</item>
+        /// <item><paramref name="hydraulicBoundaryLocation"/> is not part of <paramref name="assessmentSection"/>;</item>
+        /// <item><paramref name="hydraulicBoundaryLocation"/> contains no corresponding calculation output.</item>
+        /// </list>
+        /// </returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="assessmentSection"/>
+        /// is <c>null</c>.</exception>
+        /// <exception cref="InvalidEnumArgumentException">Thrown when <paramref name="categoryType"/>
+        /// is an invalid <see cref="AssessmentSectionCategoryType"/>.</exception>
+        /// <exception cref="NotSupportedException">Thrown when <paramref name="categoryType"/>
+        /// is a valid but unsupported <see cref="AssessmentSectionCategoryType"/>.</exception>
+        public static RoundedDouble GetAssessmentLevel(this IAssessmentSection assessmentSection,
+                                                       HydraulicBoundaryLocation hydraulicBoundaryLocation,
+                                                       AssessmentSectionCategoryType categoryType)
+        {
+            if (assessmentSection == null)
+            {
+                throw new ArgumentNullException(nameof(assessmentSection));
+            }
+
+            if (!Enum.IsDefined(typeof(AssessmentSectionCategoryType), categoryType))
+            {
+                throw new InvalidEnumArgumentException(nameof(categoryType),
+                                                       (int) categoryType,
+                                                       typeof(AssessmentSectionCategoryType));
+            }
+
+            IEnumerable<HydraulicBoundaryLocationCalculation> calculations;
+
+            switch (categoryType)
+            {
+                case AssessmentSectionCategoryType.FactorizedSignalingNorm:
+                    calculations = assessmentSection.WaterLevelCalculationsForFactorizedSignalingNorm;
+                    break;
+                case AssessmentSectionCategoryType.SignalingNorm:
+                    calculations = assessmentSection.WaterLevelCalculationsForSignalingNorm;
+                    break;
+                case AssessmentSectionCategoryType.LowerLimitNorm:
+                    calculations = assessmentSection.WaterLevelCalculationsForLowerLimitNorm;
+                    break;
+                case AssessmentSectionCategoryType.FactorizedLowerLimitNorm:
+                    calculations = assessmentSection.WaterLevelCalculationsForFactorizedLowerLimitNorm;
+                    break;
+                default:
+                    throw new NotSupportedException();
+            }
+
+            return GetAssessmentLevelFromCalculations(hydraulicBoundaryLocation, calculations);
+        }
+
+        private static RoundedDouble GetAssessmentLevelFromCalculations(HydraulicBoundaryLocation hydraulicBoundaryLocation, IEnumerable<HydraulicBoundaryLocationCalculation> calculations)
+        {
+            return calculations.FirstOrDefault(c => ReferenceEquals(c.HydraulicBoundaryLocation, hydraulicBoundaryLocation))?.Output?.Result
+                   ?? RoundedDouble.NaN;
+        }
     }
 }
\ No newline at end of file