Index: Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingSoilLayer.cs
===================================================================
diff -u -r5076e379f409c3b5ba41eb98256e3dd5d140571c -r2a49b7243807fe0b95136efd55652201164a6c74
--- Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingSoilLayer.cs	(.../PipingSoilLayer.cs)	(revision 5076e379f409c3b5ba41eb98256e3dd5d140571c)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingSoilLayer.cs	(.../PipingSoilLayer.cs)	(revision 2a49b7243807fe0b95136efd55652201164a6c74)
@@ -21,9 +21,9 @@
         public double Top { get; private set; }
 
         /// <summary>
-        /// Gets or sets the double which represents whether the <see cref="PipingSoilLayer"/> is an aquifer.
+        /// Gets or sets the boolean value which represents whether the <see cref="PipingSoilLayer"/> is an aquifer.
         /// </summary>
-        public double? IsAquifer { get; set; }
+        public bool IsAquifer { get; set; }
 
         /// <summary>
         /// Gets or sets the volumic weight of the <see cref="PipingSoilLayer"/> above the phreatic level.