diff --git a/opm/output/data/Wells.hpp b/opm/output/data/Wells.hpp
index 6d7fc3cee..982a58fa8 100644
--- a/opm/output/data/Wells.hpp
+++ b/opm/output/data/Wells.hpp
@@ -43,6 +43,7 @@ namespace Opm {
          */
 
         public:
+            Rates() = default;
             enum class opt : uint32_t {
                 wat     = (1 << 0),
                 oil     = (1 << 1),