Index: Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Forms/Factories/MacroStabilityInwardsChartDataPointsFactory.cs
===================================================================
diff -u -r566d08e1fc04c8c67b9184a2c343d75e833948d0 -recadff6f1b94fcd2a22c9963b25153a189c26dfd
--- Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Forms/Factories/MacroStabilityInwardsChartDataPointsFactory.cs	(.../MacroStabilityInwardsChartDataPointsFactory.cs)	(revision 566d08e1fc04c8c67b9184a2c343d75e833948d0)
+++ Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Forms/Factories/MacroStabilityInwardsChartDataPointsFactory.cs	(.../MacroStabilityInwardsChartDataPointsFactory.cs)	(revision ecadff6f1b94fcd2a22c9963b25153a189c26dfd)
@@ -638,6 +638,7 @@
                     }
                     else if (Math.Abs(waternetBottomDelta) < tolerance && waternetTopDelta > 0)
                     {
+                        bottomLine.Add(surfaceLineIntersection);
                         topLine.Add(surfaceLineIntersection);
                     }
                 }
@@ -647,9 +648,16 @@
             if (AreaIsNotFlatLine(topLine, bottomLine))
             {
                 area.AddRange(topLine);
-                area.AddRange(bottomLine.OrderByDescending(p => p.X));
-                if (topLine.Any())
+
+                List<Point2D> sortedBottomLine = bottomLine.OrderByDescending(p => p.X).ToList();
+                if (sortedBottomLine.First().Equals(topLine.Last()))
                 {
+                    sortedBottomLine.Remove(sortedBottomLine.First());
+                }
+
+                area.AddRange(sortedBottomLine);
+                if (topLine.Any() && !area.Last().Equals(topLine.First()))
+                {
                     area.Add(topLine.First());
                 }
             }
Index: Ringtoets/MacroStabilityInwards/test/Ringtoets.MacroStabilityInwards.Forms.Test/Factories/MacroStabilityInwardsChartDataPointsFactoryTest.cs
===================================================================
diff -u -r566d08e1fc04c8c67b9184a2c343d75e833948d0 -recadff6f1b94fcd2a22c9963b25153a189c26dfd
--- Ringtoets/MacroStabilityInwards/test/Ringtoets.MacroStabilityInwards.Forms.Test/Factories/MacroStabilityInwardsChartDataPointsFactoryTest.cs	(.../MacroStabilityInwardsChartDataPointsFactoryTest.cs)	(revision 566d08e1fc04c8c67b9184a2c343d75e833948d0)
+++ Ringtoets/MacroStabilityInwards/test/Ringtoets.MacroStabilityInwards.Forms.Test/Factories/MacroStabilityInwardsChartDataPointsFactoryTest.cs	(.../MacroStabilityInwardsChartDataPointsFactoryTest.cs)	(revision ecadff6f1b94fcd2a22c9963b25153a189c26dfd)
@@ -870,6 +870,39 @@
         }
 
         [Test]
+        public void CreateWaterNetZonePoints_PhreaticLineAboveSurfaceLineAndWaterNetLinesOnSurfaceLine_ReturnsEmptyCollection()
+        {
+            // Setup
+            var waternetLineGeometry = new[]
+            {
+                new Point2D(0, 6),
+                new Point2D(4.98, 6),
+                new Point2D(10.05, 7)
+            };
+
+            var phreaticLineGeometry = new[]
+            {
+                new Point2D(0, 10),
+                new Point2D(10.05, 10)
+            };
+
+            MacroStabilityInwardsWaternetLine waternetLine = CreateWaternetLine(waternetLineGeometry, phreaticLineGeometry);
+
+            var surfaceLine = new MacroStabilityInwardsSurfaceLine("Test");
+            surfaceLine.SetGeometry(new[]
+            {
+                new Point3D(0, 6, 6),
+                new Point3D(5, 6, 6),
+                new Point3D(10, 7, 7)
+            });
+
+            IEnumerable<IEnumerable<Point2D>> zones = MacroStabilityInwardsChartDataPointsFactory.CreateWaternetZonePoints(waternetLine, surfaceLine);
+
+            // Assert
+            CollectionAssert.IsEmpty(zones);
+        }
+
+        [Test]
         [TestCaseSource(nameof(GetPhreaticLineAndWaternetLineConfigurationsBelowSurfaceLine))]
         public void CreateWaternetZonePoints_DifferentWaternetLineAndPhreaticLineBelowSurfaceLineConfigurations_ReturnsPointsCollection(
             MacroStabilityInwardsSurfaceLine surfaceLine,
@@ -1132,7 +1165,6 @@
                 new Point2D(10, 2),
                 new Point2D(11.09, 3.74),
                 new Point2D(13, -2),
-                new Point2D(13, -2),
                 new Point2D(11.09, -2),
                 new Point2D(10, -2),
                 new Point2D(6.875, -2),
@@ -1147,7 +1179,6 @@
                 new Point2D(13, -2),
                 new Point2D(15, -2),
                 new Point2D(15, -8),
-                new Point2D(13, -2),
                 new Point2D(13, -2)
             }, zones.ElementAt(1), new Point2DComparerWithTolerance(1e-2));
         }