diff --git a/dumux/porousmediumflow/2pnc/model.hh b/dumux/porousmediumflow/2pnc/model.hh
index 5815573505c2c7fc804b9fff0d6bec088e004d23..2b9c32552ca63a25e5942a6129a6e6c816c792ee 100644
--- a/dumux/porousmediumflow/2pnc/model.hh
+++ b/dumux/porousmediumflow/2pnc/model.hh
@@ -165,6 +165,7 @@ struct TwoPNCModelTraits
             return pvIdx == 0 ? "p_w" : p0s1SwitchedPvNames[state-1];
         case TwoPFormulation::p1s0:
             return pvIdx == 0 ? "p_n" : p1s0SwitchedPvNames[state-1];
+        default: DUNE_THROW(Dune::InvalidStateException, "Invalid formulation ");
         }
     }
 };