Index: Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsInput.cs
===================================================================
diff -u -rc4392a12110e2bb3549c5fee1ec319c229b67198 -re2ef0a58393a86f83e172c7eda556b60a5ce9315
--- Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsInput.cs	(.../MacroStabilityInwardsInput.cs)	(revision c4392a12110e2bb3549c5fee1ec319c229b67198)
+++ Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsInput.cs	(.../MacroStabilityInwardsInput.cs)	(revision e2ef0a58393a86f83e172c7eda556b60a5ce9315)
@@ -56,6 +56,8 @@
         private RoundedDouble piezometricHeadPhreaticLine2Inwards;
         private RoundedDouble tangentLineZTop;
         private RoundedDouble tangentLineZBottom;
+        private RoundedDouble zoneBoundaryLeft;
+        private RoundedDouble zoneBoundaryRight;
         private int tangentLineNumber;
 
         /// <summary>
@@ -132,6 +134,9 @@
                                                       properties.RightGridZBottom);
 
             CreateZones = true;
+            ZoningBoundariesDeterminationType = MacroStabilityInwardsZoningBoundariesDeterminationType.Automatic;
+            zoneBoundaryLeft = new RoundedDouble(2, double.NaN);
+            zoneBoundaryRight = new RoundedDouble(2, double.NaN);
         }
 
         /// <summary>
@@ -679,14 +684,38 @@
         /// <summary>
         /// Gets the zoning boundaries determination type.
         /// </summary>
-        public MacroStabilityInwardsZoningBoundariesDeterminationType ZoningBoundariesDeterminationType
+        public MacroStabilityInwardsZoningBoundariesDeterminationType ZoningBoundariesDeterminationType { get; set; }
+
+        /// <summary>
+        /// Gets or sets the left zone boundary.
+        /// </summary>
+        public RoundedDouble ZoneBoundaryLeft
         {
             get
             {
-                return MacroStabilityInwardsZoningBoundariesDeterminationType.Automatic;
+                return zoneBoundaryLeft;
             }
+            set
+            {
+                zoneBoundaryLeft = value.ToPrecision(zoneBoundaryLeft.NumberOfDecimalPlaces);
+            }
         }
 
+        /// <summary>
+        /// Gets or sets the right zone boundary.
+        /// </summary>
+        public RoundedDouble ZoneBoundaryRight
+        {
+            get
+            {
+                return zoneBoundaryRight;
+            }
+            set
+            {
+                zoneBoundaryRight = value.ToPrecision(zoneBoundaryRight.NumberOfDecimalPlaces);
+            }
+        }
+
         #endregion
     }
 }
\ No newline at end of file