diff --git a/MaterialLib/PorousMedium/Porosity/ConstantPorosity.h b/MaterialLib/PorousMedium/Porosity/ConstantPorosity.h
index 19a6b02cddc968ec89882e627a6237b024e140dc..6c78ae51f88ab40329e758f0463f99b3519ef5f2 100644
--- a/MaterialLib/PorousMedium/Porosity/ConstantPorosity.h
+++ b/MaterialLib/PorousMedium/Porosity/ConstantPorosity.h
@@ -31,7 +31,7 @@ public:
      *  @param variable    A variable with any double type value.
      *  @param temperature Temperature with any double type value.
      */
-    double getValue(const double variable, double temperature) const override
+    double getValue(const double variable, const double temperature) const override
     {
         (void)variable;
         (void)temperature;
diff --git a/MaterialLib/PorousMedium/Porosity/Porosity.h b/MaterialLib/PorousMedium/Porosity/Porosity.h
index a2cf8e3bdc4b5540b4bc41af4ded21772476f67a..950008bebc981956bc26462bdb6f674d7af04f36 100644
--- a/MaterialLib/PorousMedium/Porosity/Porosity.h
+++ b/MaterialLib/PorousMedium/Porosity/Porosity.h
@@ -33,7 +33,7 @@ public:
      *  @param temperature Temperature.
      */
     virtual double getValue(const double variable,
-                            double temperature) const = 0;
+                            const double temperature) const = 0;
 };
 
 }  // end of namespace