Index: Ringtoets/GrassCoverErosionInwards/test/Ringtoets.GrassCoverErosionInwards.Data.Test/GrassCoverErosionInwardsInputTest.cs
===================================================================
diff -u -r5b2327e0eea8a6fb1e51198ba41c1c74b4676e7c -rd859a8308857ce1bf82ff94356a30363213c6ff6
--- Ringtoets/GrassCoverErosionInwards/test/Ringtoets.GrassCoverErosionInwards.Data.Test/GrassCoverErosionInwardsInputTest.cs	(.../GrassCoverErosionInwardsInputTest.cs)	(revision 5b2327e0eea8a6fb1e51198ba41c1c74b4676e7c)
+++ Ringtoets/GrassCoverErosionInwards/test/Ringtoets.GrassCoverErosionInwards.Data.Test/GrassCoverErosionInwardsInputTest.cs	(.../GrassCoverErosionInwardsInputTest.cs)	(revision d859a8308857ce1bf82ff94356a30363213c6ff6)
@@ -19,6 +19,7 @@
 // Stichting Deltares and remain full property of Stichting Deltares at all times.
 // All rights reserved.
 
+using System;
 using System.Collections.Generic;
 using Core.Common.Base;
 using Core.Common.Base.Data;
@@ -225,25 +226,27 @@
         public void CriticalFlowRate_SetNewValue_GetNewValues()
         {
             // Setup
-            const double meanValue = 1.2345689;
-            const double standardDeviationValue = 9.87654321;
+            var random = new Random(22);
             var input = new GrassCoverErosionInwardsInput();
-
-            int originalNumberOfDecimalPlacesMean = input.CriticalFlowRate.Mean.NumberOfDecimalPlaces;
-            int originalNumberOfDecimalPlacesStandardDeviation = input.CriticalFlowRate.StandardDeviation.NumberOfDecimalPlaces;
-
-            // Call
-            input.CriticalFlowRate = new LogNormalDistribution(10)
+            var mean = (RoundedDouble)(0.01 + random.NextDouble());
+            var standardDeviation = (RoundedDouble)(0.01 + random.NextDouble());
+            var expectedDistribution = new LogNormalDistribution(4)
             {
-                Mean = (RoundedDouble) meanValue,
-                StandardDeviation = (RoundedDouble) standardDeviationValue
+                Mean = mean,
+                StandardDeviation = standardDeviation
             };
+            var distributionToSet = new LogNormalDistribution(5)
+            {
+                Mean = mean,
+                StandardDeviation = standardDeviation
+            };
 
+            // Call
+            input.CriticalFlowRate = distributionToSet;
+
             // Assert
-            Assert.AreEqual(originalNumberOfDecimalPlacesMean, input.CriticalFlowRate.Mean.NumberOfDecimalPlaces);
-            Assert.AreEqual(new RoundedDouble(originalNumberOfDecimalPlacesMean, meanValue), input.CriticalFlowRate.Mean);
-            Assert.AreEqual(originalNumberOfDecimalPlacesStandardDeviation, input.CriticalFlowRate.StandardDeviation.NumberOfDecimalPlaces);
-            Assert.AreEqual(new RoundedDouble(originalNumberOfDecimalPlacesStandardDeviation, standardDeviationValue), input.CriticalFlowRate.StandardDeviation);
+            Assert.AreNotSame(distributionToSet, input.CriticalFlowRate);
+            DistributionAssert.AreEqual(expectedDistribution, input.CriticalFlowRate);
         }
     }
 }
\ No newline at end of file
Index: Ringtoets/Piping/test/Ringtoets.Piping.Data.Test/PipingInputTest.cs
===================================================================
diff -u -r8c4f2c495cacd793914ec618d43d21e0fa506401 -rd859a8308857ce1bf82ff94356a30363213c6ff6
--- Ringtoets/Piping/test/Ringtoets.Piping.Data.Test/PipingInputTest.cs	(.../PipingInputTest.cs)	(revision 8c4f2c495cacd793914ec618d43d21e0fa506401)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Data.Test/PipingInputTest.cs	(.../PipingInputTest.cs)	(revision d859a8308857ce1bf82ff94356a30363213c6ff6)
@@ -330,50 +330,52 @@
         public void PhreaticLevelExit_SetNewValue_UpdateMeanAndStandardDeviation()
         {
             // Setup
-            PipingInput inputs = new PipingInput(new GeneralPipingInput());
-            NormalDistribution originalPhreaticLevelExit = inputs.PhreaticLevelExit;
-
-            NormalDistribution newValue = new NormalDistribution(5)
+            var random = new Random(22);
+            var input = new PipingInput(new GeneralPipingInput());
+            var mean = (RoundedDouble) (0.01 + random.NextDouble());
+            var standardDeviation = (RoundedDouble) (0.01 + random.NextDouble());
+            var expectedDistribution = new NormalDistribution(3)
             {
-                Mean = (RoundedDouble) 1.23456,
-                StandardDeviation = (RoundedDouble) 7.89123
+                Mean = mean,
+                StandardDeviation = standardDeviation
             };
+            var distributionToSet = new NormalDistribution(5)
+            {
+                Mean = mean,
+                StandardDeviation = standardDeviation
+            };
 
             // Call
-            inputs.PhreaticLevelExit = newValue;
+            input.PhreaticLevelExit = distributionToSet;
 
             // Assert
-            Assert.AreSame(originalPhreaticLevelExit, inputs.PhreaticLevelExit,
-                           "Stochast instance hasn't changed to 'newValue'.");
-            Assert.AreEqual(3, originalPhreaticLevelExit.Mean.NumberOfDecimalPlaces);
-            Assert.AreEqual(1.235, originalPhreaticLevelExit.Mean.Value);
-            Assert.AreEqual(3, originalPhreaticLevelExit.StandardDeviation.NumberOfDecimalPlaces);
-            Assert.AreEqual(7.891, originalPhreaticLevelExit.StandardDeviation.Value);
+            AssertDistributionCorrectlySet(input.PhreaticLevelExit, distributionToSet, expectedDistribution);
         }
 
         [Test]
         public void DampingFactorExit_SetNewValue_UpdateMeanAndStandardDeviation()
         {
             // Setup
-            PipingInput inputs = new PipingInput(new GeneralPipingInput());
-            LogNormalDistribution originalDampingFactorExit = inputs.DampingFactorExit;
-
-            LogNormalDistribution newValue = new LogNormalDistribution(5)
+            var random = new Random(22);
+            var input = new PipingInput(new GeneralPipingInput());
+            var mean = (RoundedDouble) (0.01 + random.NextDouble());
+            var standardDeviation = (RoundedDouble) (0.01 + random.NextDouble());
+            var expectedDistribution = new LogNormalDistribution(3)
             {
-                Mean = (RoundedDouble) 4.56789,
-                StandardDeviation = (RoundedDouble) 1.23456
+                Mean = mean,
+                StandardDeviation = standardDeviation
             };
+            var distributionToSet = new LogNormalDistribution(5)
+            {
+                Mean = mean,
+                StandardDeviation = standardDeviation
+            };
 
             // Call
-            inputs.DampingFactorExit = newValue;
+            input.DampingFactorExit = distributionToSet;
 
             // Assert
-            Assert.AreSame(originalDampingFactorExit, inputs.DampingFactorExit,
-                           "Stochast instance hasn't changed to 'newValue'.");
-            Assert.AreEqual(3, originalDampingFactorExit.Mean.NumberOfDecimalPlaces);
-            Assert.AreEqual(4.568, originalDampingFactorExit.Mean.Value);
-            Assert.AreEqual(3, originalDampingFactorExit.StandardDeviation.NumberOfDecimalPlaces);
-            Assert.AreEqual(1.235, originalDampingFactorExit.StandardDeviation.Value);
+            AssertDistributionCorrectlySet(input.DampingFactorExit, distributionToSet, expectedDistribution);
         }
 
         [Test]
@@ -807,5 +809,11 @@
 
             return surfaceLine;
         }
+
+        private static void AssertDistributionCorrectlySet(IDistribution distributionToAssert, IDistribution setDistribution, IDistribution expectedDistribution)
+        {
+            Assert.AreNotSame(setDistribution, distributionToAssert);
+            DistributionAssert.AreEqual(expectedDistribution, distributionToAssert);
+        }
     }
 }
\ No newline at end of file