diff --git a/build/cmake/CMakeLists.txt b/build/cmake/CMakeLists.txt
index 8fb6f8032cef870a5b7a838a4771d978fe2515fd..91096073b573c0eb80f4949cc4a8ccf3d0d05bee 100644
--- a/build/cmake/CMakeLists.txt
+++ b/build/cmake/CMakeLists.txt
@@ -294,7 +294,7 @@ if (SUNDIALS)
             SUMMA_NOAHMP
             -lnetcdff)
 
-    set(CMAKE_CXX_FLAGS "-g -O0 -Wfatal-errors -std=c++17")
+    set(CMAKE_CXX_FLAGS "-g -O3 -Wfatal-errors -std=c++17")