diff --git a/dumux/linear/amgbackend.hh b/dumux/linear/amgbackend.hh
index 840933a97afea369ecc0b55a7bbe74cf0ba5642e..92435484814c0b2a02c25f3bebb1d78f451ede6b 100644
--- a/dumux/linear/amgbackend.hh
+++ b/dumux/linear/amgbackend.hh
@@ -82,8 +82,10 @@ public:
                        const typename LinearSolverTraits::DofMapper& dofMapper,
                        const std::string& paramGroup = "")
     : LinearSolver(paramGroup)
-    , phelper_(std::make_shared<ParallelISTLHelper<LinearSolverTraits>>(gridView, dofMapper))
+#if HAVE_MPI
+    , phelper_(std::make_unique<ParallelISTLHelper<LinearSolverTraits>>(gridView, dofMapper))
     , isParallel_(Dune::MPIHelper::getCollectiveCommunication().size() > 1)
+#endif
     {
         reset();
     }
@@ -224,9 +226,11 @@ private:
         solver.apply(x, b, result_);
     }
 
-    std::shared_ptr<ParallelISTLHelper<LinearSolverTraits>> phelper_;
+#if HAVE_MPI
+    std::unique_ptr<ParallelISTLHelper<LinearSolverTraits>> phelper_;
+#endif
     Dune::InverseOperatorResult result_;
-    bool isParallel_;
+    bool isParallel_ = false;
     bool firstCall_;
 };
 
diff --git a/dumux/linear/istlsolverfactorybackend.hh b/dumux/linear/istlsolverfactorybackend.hh
index fa96f2e425911fd2dda0f43b905309f459319c43..71e330eb9c9295830fdd06debf558ef43649c5d0 100644
--- a/dumux/linear/istlsolverfactorybackend.hh
+++ b/dumux/linear/istlsolverfactorybackend.hh
@@ -85,8 +85,10 @@ public:
                              const typename LinearSolverTraits::DofMapper& dofMapper,
                              const std::string& paramGroup = "")
     : paramGroup_(paramGroup)
+#if HAVE_MPI
     , parallelHelper_(std::make_unique<ParallelISTLHelper<LinearSolverTraits>>(gridView, dofMapper))
     , isParallel_(Dune::MPIHelper::getCollectiveCommunication().size() > 1)
+#endif
     {
         reset();
     }
@@ -227,8 +229,10 @@ private:
     }
 
     const std::string paramGroup_;
+#if HAVE_MPI
     std::unique_ptr<ParallelISTLHelper<LinearSolverTraits>> parallelHelper_;
-    bool isParallel_;
+#endif
+    bool isParallel_ = false;
     bool firstCall_;
 
     Dune::InverseOperatorResult result_;
diff --git a/dumux/linear/linearsolvertraits.hh b/dumux/linear/linearsolvertraits.hh
index dcca6e0a7565ffda191065495f3ccd56dde3529e..154071021c4551d148cc1c349c73ee30a5ee5f8d 100644
--- a/dumux/linear/linearsolvertraits.hh
+++ b/dumux/linear/linearsolvertraits.hh
@@ -125,11 +125,13 @@ struct LinearSolverTraitsBase
     template<class Matrix, class Vector>
     using Sequential = SequentialSolverTraits<Matrix, Vector>;
 
+#if HAVE_MPI
     template<class Matrix, class Vector>
     using ParallelOverlapping = OverlappingSolverTraits<Matrix, Vector>;
 
     template<class Matrix, class Vector>
     using ParallelNonoverlapping = NonoverlappingSolverTraits<Matrix, Vector>;
+#endif
 };
 
 //! Box: use overlapping or non-overlapping model depending on the grid