Index: Ringtoets/Integration/src/Ringtoets.Integration.Forms/Properties/Resources.Designer.cs
===================================================================
diff -u -r6960c6d71475e60772aaaf95b0690793c18f775c -r0bf7bef98d08bd001d4c999443ce5f4e8761c674
--- Ringtoets/Integration/src/Ringtoets.Integration.Forms/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision 6960c6d71475e60772aaaf95b0690793c18f775c)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Forms/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision 0bf7bef98d08bd001d4c999443ce5f4e8761c674)
@@ -352,6 +352,16 @@
         }
         
         /// <summary>
+        ///   Looks up a localized string similar to De waarde voor de &apos;Norm&apos; moet in het bereik [100, 1000000] liggen..
+        /// </summary>
+        public static string FailureMechanismContributionContextProperties_ReturnPeriod_Value_for_ReturnPeriod_Must_be_in_range_100_to_1000000 {
+            get {
+                return ResourceManager.GetString("FailureMechanismContributionContextProperties_ReturnPeriod_Value_for_ReturnPeriod" +
+                        "_Must_be_in_range_100_to_1000000", resourceCulture);
+            }
+        }
+        
+        /// <summary>
         ///   Looks up a localized string similar to Dijk.
         /// </summary>
         public static string FailureMechanismContributionView_InitializeAssessmentSectionCompositionComboBox_Dike {
Index: Ringtoets/Integration/src/Ringtoets.Integration.Forms/Properties/Resources.resx
===================================================================
diff -u -r6960c6d71475e60772aaaf95b0690793c18f775c -r0bf7bef98d08bd001d4c999443ce5f4e8761c674
--- Ringtoets/Integration/src/Ringtoets.Integration.Forms/Properties/Resources.resx	(.../Resources.resx)	(revision 6960c6d71475e60772aaaf95b0690793c18f775c)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Forms/Properties/Resources.resx	(.../Resources.resx)	(revision 0bf7bef98d08bd001d4c999443ce5f4e8761c674)
@@ -297,4 +297,7 @@
   <data name="FailureMechanismContribution_ReturnPeriod_DisplayName" xml:space="preserve">
     <value>Norm [1/jaar]</value>
   </data>
+  <data name="FailureMechanismContributionContextProperties_ReturnPeriod_Value_for_ReturnPeriod_Must_be_in_range_100_to_1000000" xml:space="preserve">
+    <value>De waarde voor de 'Norm' moet in het bereik [100, 1000000] liggen.</value>
+  </data>
 </root>
\ No newline at end of file
Index: Ringtoets/Integration/src/Ringtoets.Integration.Forms/PropertyClasses/FailureMechanismContributionContextProperties.cs
===================================================================
diff -u -r0916bc9808f7c527e16e75a5404b800d2bd223c5 -r0bf7bef98d08bd001d4c999443ce5f4e8761c674
--- Ringtoets/Integration/src/Ringtoets.Integration.Forms/PropertyClasses/FailureMechanismContributionContextProperties.cs	(.../FailureMechanismContributionContextProperties.cs)	(revision 0916bc9808f7c527e16e75a5404b800d2bd223c5)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Forms/PropertyClasses/FailureMechanismContributionContextProperties.cs	(.../FailureMechanismContributionContextProperties.cs)	(revision 0bf7bef98d08bd001d4c999443ce5f4e8761c674)
@@ -80,6 +80,11 @@
             }
             set
             {
+                if (value < 100 || value > 1000000)
+                {
+                    throw new ArgumentOutOfRangeException("value", Resources.FailureMechanismContributionContextProperties_ReturnPeriod_Value_for_ReturnPeriod_Must_be_in_range_100_to_1000000);
+                }
+
                 if (value != 0 && normChangeHandler.ConfirmNormChange())
                 {
                     double newNormValue = 1.0/Convert.ToInt32(value);
Index: Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/PropertyClasses/FailureMechanismContributionContextPropertiesTest.cs
===================================================================
diff -u -r04a75d409f31056c8a55a8a97dc3f511c25ff212 -r0bf7bef98d08bd001d4c999443ce5f4e8761c674
--- Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/PropertyClasses/FailureMechanismContributionContextPropertiesTest.cs	(.../FailureMechanismContributionContextPropertiesTest.cs)	(revision 04a75d409f31056c8a55a8a97dc3f511c25ff212)
+++ Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/PropertyClasses/FailureMechanismContributionContextPropertiesTest.cs	(.../FailureMechanismContributionContextPropertiesTest.cs)	(revision 0bf7bef98d08bd001d4c999443ce5f4e8761c674)
@@ -106,16 +106,19 @@
             var failureMechanisms = Enumerable.Empty<IFailureMechanism>();
             var contribution = new FailureMechanismContribution(failureMechanisms, 1.1, 1.0/returnPeriod);
 
-            // Call
             var properties = new FailureMechanismContributionContextProperties()
             {
                 Data = contribution,
                 AssessmentSection = assessmentSection
             };
 
+            // Call
+            int returnPeriodPropertyValue = properties.ReturnPeriod;
+            AssessmentSectionComposition compositionPropertyValue = properties.AssessmentSectionComposition;
+
             // Assert
-            Assert.AreEqual(returnPeriod, properties.ReturnPeriod);
-            Assert.AreEqual(assessmentSectionComposition, properties.AssessmentSectionComposition);
+            Assert.AreEqual(returnPeriod, returnPeriodPropertyValue);
+            Assert.AreEqual(assessmentSectionComposition, compositionPropertyValue);
             mocks.VerifyAll();
         }
 
@@ -306,6 +309,36 @@
         }
 
         [Test]
+        [TestCase(int.MinValue)]
+        [TestCase(int.MaxValue)]
+        [TestCase(99)]
+        [TestCase(1000001)]
+        public void ReturnPeriod_InvalidValue_ThrowsArgumentOutOfRangeException(int invalidReturnPeriod)
+        {
+            // Setup
+            var assessmentSectionComposition = AssessmentSectionComposition.DikeAndDune;
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
+            assessmentSection.Stub(section => section.Composition).Return(assessmentSectionComposition);
+            mocks.ReplayAll();
+
+            var failureMechanisms = Enumerable.Empty<IFailureMechanism>();
+            var contribution = new FailureMechanismContribution(failureMechanisms, 1.1, 1.0/200);
+
+            var properties = new FailureMechanismContributionContextProperties()
+            {
+                Data = contribution,
+                AssessmentSection = assessmentSection
+            };
+
+            // Call
+            TestDelegate call = () => properties.ReturnPeriod = invalidReturnPeriod;
+
+            // Assert
+            TestHelper.AssertThrowsArgumentExceptionAndTestMessage<ArgumentOutOfRangeException>(call,
+                                                                                                "De waarde voor de 'Norm' moet in het bereik [100, 1000000] liggen.");
+        }
+
+        [Test]
         [TestCase(AssessmentSectionComposition.Dike, AssessmentSectionComposition.Dune)]
         [TestCase(AssessmentSectionComposition.Dike, AssessmentSectionComposition.DikeAndDune)]
         [TestCase(AssessmentSectionComposition.Dune, AssessmentSectionComposition.Dike)]
@@ -327,10 +360,10 @@
                                     .Return(true);
             compositionChangeHandler.Expect(h => h.ChangeComposition(assessmentSection, newComposition))
                                     .Return(new[]
-								{
-									observable1,
-									observable2
-								});
+                                    {
+                                        observable1,
+                                        observable2
+                                    });
             mocks.ReplayAll();
 
             var properties = new FailureMechanismContributionContextProperties()