diff --git a/wxdata/include/scwx/awips/phenomenon.hpp b/wxdata/include/scwx/awips/phenomenon.hpp
index 376241cd..013a9947 100644
--- a/wxdata/include/scwx/awips/phenomenon.hpp
+++ b/wxdata/include/scwx/awips/phenomenon.hpp
@@ -68,9 +68,9 @@ enum class Phenomenon
    Unknown
 };
 
-Phenomenon  GetPhenomenon(const std::string& code);
-std::string GetPhenomenonCode(Phenomenon phenomenon);
-std::string GetPhenomenonText(Phenomenon phenomenon);
+Phenomenon         GetPhenomenon(const std::string& code);
+const std::string& GetPhenomenonCode(Phenomenon phenomenon);
+const std::string& GetPhenomenonText(Phenomenon phenomenon);
 
 } // namespace awips
 } // namespace scwx
diff --git a/wxdata/include/scwx/awips/pvtec.hpp b/wxdata/include/scwx/awips/pvtec.hpp
index 405fe9ac..3b267525 100644
--- a/wxdata/include/scwx/awips/pvtec.hpp
+++ b/wxdata/include/scwx/awips/pvtec.hpp
@@ -61,11 +61,11 @@ public:
 
    bool Parse(const std::string& s);
 
-   static ProductType GetProductType(const std::string& code);
-   static std::string GetProductTypeCode(ProductType productType);
+   static ProductType        GetProductType(const std::string& code);
+   static const std::string& GetProductTypeCode(ProductType productType);
 
-   static Action      GetAction(const std::string& code);
-   static std::string GetActionCode(Action action);
+   static Action             GetAction(const std::string& code);
+   static const std::string& GetActionCode(Action action);
 
 private:
    std::unique_ptr<PVtecImpl> p;
diff --git a/wxdata/include/scwx/awips/significance.hpp b/wxdata/include/scwx/awips/significance.hpp
index f2250300..fb24cee8 100644
--- a/wxdata/include/scwx/awips/significance.hpp
+++ b/wxdata/include/scwx/awips/significance.hpp
@@ -19,9 +19,9 @@ enum class Significance
    Unknown
 };
 
-Significance GetSignificance(const std::string& code);
-std::string  GetSignificanceCode(Significance significance);
-std::string  GetSignificanceText(Significance significance);
+Significance       GetSignificance(const std::string& code);
+const std::string& GetSignificanceCode(Significance significance);
+const std::string& GetSignificanceText(Significance significance);
 
 } // namespace awips
 } // namespace scwx
diff --git a/wxdata/source/scwx/awips/phenomenon.cpp b/wxdata/source/scwx/awips/phenomenon.cpp
index 4e14c061..ea97fe3f 100644
--- a/wxdata/source/scwx/awips/phenomenon.cpp
+++ b/wxdata/source/scwx/awips/phenomenon.cpp
@@ -154,12 +154,12 @@ Phenomenon GetPhenomenon(const std::string& code)
    return phenomenon;
 }
 
-std::string GetPhenomenonCode(Phenomenon phenomenon)
+const std::string& GetPhenomenonCode(Phenomenon phenomenon)
 {
    return phenomenonCodes_.left.at(phenomenon);
 }
 
-std::string GetPhenomenonText(Phenomenon phenomenon)
+const std::string& GetPhenomenonText(Phenomenon phenomenon)
 {
    return phenomenonText_.at(phenomenon);
 }
diff --git a/wxdata/source/scwx/awips/pvtec.cpp b/wxdata/source/scwx/awips/pvtec.cpp
index 4e5f20e5..e8987052 100644
--- a/wxdata/source/scwx/awips/pvtec.cpp
+++ b/wxdata/source/scwx/awips/pvtec.cpp
@@ -242,7 +242,7 @@ PVtec::ProductType PVtec::GetProductType(const std::string& code)
    return productType;
 }
 
-std::string PVtec::GetProductTypeCode(PVtec::ProductType productType)
+const std::string& PVtec::GetProductTypeCode(PVtec::ProductType productType)
 {
    return productTypeCodes_.left.at(productType);
 }
@@ -266,7 +266,7 @@ PVtec::Action PVtec::GetAction(const std::string& code)
    return action;
 }
 
-std::string PVtec::GetActionCode(PVtec::Action action)
+const std::string& PVtec::GetActionCode(PVtec::Action action)
 {
    return actionCodes_.left.at(action);
 }
diff --git a/wxdata/source/scwx/awips/significance.cpp b/wxdata/source/scwx/awips/significance.cpp
index a4a29e7c..0be08056 100644
--- a/wxdata/source/scwx/awips/significance.cpp
+++ b/wxdata/source/scwx/awips/significance.cpp
@@ -56,12 +56,12 @@ Significance GetSignificance(const std::string& code)
    return significance;
 }
 
-std::string GetSignificanceCode(Significance significance)
+const std::string& GetSignificanceCode(Significance significance)
 {
    return significanceCodes_.left.at(significance);
 }
 
-std::string GetSignificanceText(Significance significance)
+const std::string& GetSignificanceText(Significance significance)
 {
    return significanceText_.at(significance);
 }