diff --git a/opm/core/fluid/SaturationPropsBasic.cpp b/opm/core/fluid/SaturationPropsBasic.cpp
index 077576b04..b168abe6d 100644
--- a/opm/core/fluid/SaturationPropsBasic.cpp
+++ b/opm/core/fluid/SaturationPropsBasic.cpp
@@ -128,6 +128,15 @@ namespace Opm
 
 
 
+    /// \return   P, the number of phases.
+    int SaturationPropsBasic::numPhases() const
+    {
+	return num_phases_;
+    }
+
+
+
+
     /// Relative permeability.
     /// \param[in]  n      Number of data points.
     /// \param[in]  s      Array of nP saturation values.
diff --git a/opm/core/fluid/SaturationPropsBasic.hpp b/opm/core/fluid/SaturationPropsBasic.hpp
index 3a8e97fa4..62ce1148c 100644
--- a/opm/core/fluid/SaturationPropsBasic.hpp
+++ b/opm/core/fluid/SaturationPropsBasic.hpp
@@ -30,6 +30,9 @@ namespace Opm
     /// by which we mean constant, linear or quadratic relative
     /// permeability functions for a maximum of two phases,
     /// and zero capillary pressure.
+    ///
+    /// TODO: This class can easily be extended to three phases,
+    /// by adding three-phase relperm behaviour.
     class SaturationPropsBasic
     {
     public:
@@ -42,6 +45,9 @@ namespace Opm
 	///    relperm_func ("Linear")   Must be "Constant", "Linear" or "Quadratic".
         void init(const Dune::parameter::ParameterGroup& param);
 
+        /// \return   P, the number of phases.
+        int numPhases() const;
+
         /// Relative permeability.
         /// \param[in]  n      Number of data points.
         /// \param[in]  s      Array of nP saturation values.
diff --git a/opm/core/fluid/SaturationPropsFromDeck.hpp b/opm/core/fluid/SaturationPropsFromDeck.hpp
index c705b39b6..f745f2e9d 100644
--- a/opm/core/fluid/SaturationPropsFromDeck.hpp
+++ b/opm/core/fluid/SaturationPropsFromDeck.hpp
@@ -36,6 +36,9 @@ namespace Opm
         /// Initialize from deck.
         void init(const Dune::EclipseGridParser& deck);
 
+        /// \return   P, the number of phases.
+        int numPhases() const;
+
         /// Relative permeability.
         /// \param[in]  n      Number of data points.
         /// \param[in]  s      Array of nP saturation values.