Index: Ringtoets/Integration/src/Ringtoets.Integration.Plugin/Merge/AssessmentSectionMergeHandler.cs
===================================================================
diff -u -r0a3fd57580aff0d6487e195c67f315f628b1ced4 -r0e8bf535243adfcc29b018dfc06609dcea1c546f
--- Ringtoets/Integration/src/Ringtoets.Integration.Plugin/Merge/AssessmentSectionMergeHandler.cs	(.../AssessmentSectionMergeHandler.cs)	(revision 0a3fd57580aff0d6487e195c67f315f628b1ced4)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Plugin/Merge/AssessmentSectionMergeHandler.cs	(.../AssessmentSectionMergeHandler.cs)	(revision 0e8bf535243adfcc29b018dfc06609dcea1c546f)
@@ -21,8 +21,10 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using Core.Common.Gui.Commands;
 using Ringtoets.Common.Data.FailureMechanism;
+using Ringtoets.Common.Data.Hydraulics;
 using Ringtoets.Integration.Data;
 
 namespace Ringtoets.Integration.Plugin.Merge
@@ -70,8 +72,37 @@
             }
 
             BeforeMerge(targetAssessmentSection);
+            MergeHydraulicBoundaryLocations(targetAssessmentSection, sourceAssessmentSection);
         }
 
+        private void MergeHydraulicBoundaryLocations(AssessmentSection targetAssessmentSection, AssessmentSection sourceAssessmentSection)
+        {
+            for (var i = 0; i < targetAssessmentSection.HydraulicBoundaryDatabase.Locations.Count; i++)
+            {
+                HydraulicBoundaryLocationCalculation targetCalculation = targetAssessmentSection.WaterLevelCalculationsForFactorizedSignalingNorm.ElementAt(i);
+                HydraulicBoundaryLocationCalculation sourceCalculation = sourceAssessmentSection.WaterLevelCalculationsForFactorizedSignalingNorm.ElementAt(i);
+
+                if (ShouldMerge(targetCalculation, sourceCalculation))
+                {
+                    targetCalculation.Output = sourceCalculation.Output;
+                }
+            }
+        }
+
+        private bool ShouldMerge(HydraulicBoundaryLocationCalculation targetCalculation, HydraulicBoundaryLocationCalculation sourceCalculation)
+        {
+            bool targetCalculationHasOutput = targetCalculation.HasOutput;
+            bool sourceCalculationHasOutput = sourceCalculation.HasOutput;
+
+            if (!targetCalculationHasOutput && !sourceCalculationHasOutput 
+                || targetCalculationHasOutput && !sourceCalculationHasOutput)
+            {
+                return false;
+            }
+
+            return true;
+        }
+
         private void BeforeMerge(AssessmentSection assessmentSection)
         {
             viewCommands.RemoveAllViewsForItem(assessmentSection);