Index: Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Service.Test/GrassCoverErosionOutwardsDataSynchronizationServiceTest.cs
===================================================================
diff -u -rac8798cf0a66cf04df1294d4fd08e0b1915a5b91 -rcd6f013c9e443af060f847d4b6b018a40948e329
--- Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Service.Test/GrassCoverErosionOutwardsDataSynchronizationServiceTest.cs	(.../GrassCoverErosionOutwardsDataSynchronizationServiceTest.cs)	(revision ac8798cf0a66cf04df1294d4fd08e0b1915a5b91)
+++ Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Service.Test/GrassCoverErosionOutwardsDataSynchronizationServiceTest.cs	(.../GrassCoverErosionOutwardsDataSynchronizationServiceTest.cs)	(revision cd6f013c9e443af060f847d4b6b018a40948e329)
@@ -26,8 +26,10 @@
 using NUnit.Framework;
 using Ringtoets.Common.Data.Calculation;
 using Ringtoets.Common.Data.Hydraulics;
+using Ringtoets.Common.Data.TestUtil;
 using Ringtoets.Common.Service;
 using Ringtoets.GrassCoverErosionOutwards.Data;
+using Ringtoets.GrassCoverErosionOutwards.Util.TestUtil;
 using Ringtoets.Revetment.Data;
 
 namespace Ringtoets.GrassCoverErosionOutwards.Service.Test
@@ -202,6 +204,55 @@
             CollectionAssert.AreEquivalent(expectedRemovedObjects, results.RemovedObjects);
         }
 
+        [Test]
+        public void ClearHydraulicBoundaryLocationCalculationOutputs_FailureMechanismNull_ThrowsArgumentNullException()
+        {
+            // Call
+            TestDelegate call = () => GrassCoverErosionOutwardsDataSynchronizationService.ClearHydraulicBoundaryLocationCalculationOutputs(null);
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(call);
+            Assert.AreEqual("failureMechanism", exception.ParamName);
+        }
+
+        [Test]
+        public void ClearHydraulicBoundaryLocationCalculationOutputs_FailureMechanismWithOutputs_OutputClearedAndAffectedItemsReturned()
+        {
+            // Setup
+            var hydraulicBoundaryLocations = new[]
+            {
+                new TestHydraulicBoundaryLocation(),
+                new TestHydraulicBoundaryLocation()
+            };
+
+            var failureMechanism = new GrassCoverErosionOutwardsFailureMechanism();
+            failureMechanism.SetHydraulicBoundaryLocationCalculations(hydraulicBoundaryLocations);
+
+            failureMechanism.WaterLevelCalculationsForMechanismSpecificFactorizedSignalingNorm.First().Output = new TestHydraulicBoundaryLocationOutput();
+            failureMechanism.WaterLevelCalculationsForMechanismSpecificSignalingNorm.First().Output = new TestHydraulicBoundaryLocationOutput();
+            failureMechanism.WaterLevelCalculationsForMechanismSpecificLowerLimitNorm.First().Output = new TestHydraulicBoundaryLocationOutput();
+            failureMechanism.WaveHeightCalculationsForMechanismSpecificFactorizedSignalingNorm.First().Output = new TestHydraulicBoundaryLocationOutput();
+            failureMechanism.WaveHeightCalculationsForMechanismSpecificSignalingNorm.First().Output = new TestHydraulicBoundaryLocationOutput();
+            failureMechanism.WaveHeightCalculationsForMechanismSpecificLowerLimitNorm.First().Output = new TestHydraulicBoundaryLocationOutput();
+
+            IEnumerable<HydraulicBoundaryLocationCalculation> expectedAffectedItems =
+                GrassCoverErosionOutwardsHydraulicBoundaryLocationsTestHelper.GetAllHydraulicBoundaryLocationsCalculationsWithOutput(failureMechanism)
+                                                                             .ToArray();
+
+            // Call
+            IEnumerable<IObservable> affectedItems = GrassCoverErosionOutwardsDataSynchronizationService.ClearHydraulicBoundaryLocationCalculationOutputs(failureMechanism);
+
+            // Assert
+            CollectionAssert.AreEquivalent(expectedAffectedItems, affectedItems);
+
+            Assert.IsTrue(failureMechanism.WaterLevelCalculationsForMechanismSpecificFactorizedSignalingNorm.All(calc => !calc.HasOutput));
+            Assert.IsTrue(failureMechanism.WaterLevelCalculationsForMechanismSpecificSignalingNorm.All(calc => !calc.HasOutput));
+            Assert.IsTrue(failureMechanism.WaterLevelCalculationsForMechanismSpecificLowerLimitNorm.All(calc => !calc.HasOutput));
+            Assert.IsTrue(failureMechanism.WaveHeightCalculationsForMechanismSpecificFactorizedSignalingNorm.All(calc => !calc.HasOutput));
+            Assert.IsTrue(failureMechanism.WaveHeightCalculationsForMechanismSpecificSignalingNorm.All(calc => !calc.HasOutput));
+            Assert.IsTrue(failureMechanism.WaveHeightCalculationsForMechanismSpecificLowerLimitNorm.All(calc => !calc.HasOutput));
+        }
+
         private static GrassCoverErosionOutwardsFailureMechanism CreateFullyConfiguredFailureMechanism()
         {
             var failureMechanism = new GrassCoverErosionOutwardsFailureMechanism();