diff --git a/.github/workflows/extbuild.yml b/.github/workflows/extbuild.yml
index 625d6bfef..c3a54360e 100644
--- a/.github/workflows/extbuild.yml
+++ b/.github/workflows/extbuild.yml
@@ -99,6 +99,6 @@ jobs:
           export SRC_ROOT=
           mkdir build-cdeps
           pushd build-cdeps
-          cmake -Wno-dev -DCMAKE_BUILD_TYPE=DEBUG -DCMAKE_Fortran_FLAGS="-DCPRGNU -g -Wall -ffree-form -ffree-line-length-none -fallow-argument-mismatch -Wno-unused-dummy-argument " -DWERROR=ON ../
+          cmake -Wno-dev -DCMAKE_BUILD_TYPE=DEBUG -DCMAKE_Fortran_FLAGS="-DCPRGNU -g -Wall -ffree-form -ffree-line-length-none -fallow-argument-mismatch " -DWERROR=ON ../
           make VERBOSE=1
           popd
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d019fd093..c3ba8afc1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -100,7 +100,7 @@ foreach(COMP datm dice dlnd docn drof dwav)
                                             $<INSTALL_INTERFACE:mod>)
 
   if(WERROR)
-     target_compile_options(${COMP} PRIVATE -Werror)
+     target_compile_options(${COMP} PRIVATE -Werror --warn-no-unused-dummy-argument)
   endif()
   install(TARGETS ${COMP}
           EXPORT  ${COMP}
@@ -118,7 +118,7 @@ foreach(DEPS streams dshr cdeps_share FoX_dom FoX_wxml FoX_sax FoX_common FoX_ut
   string(SUBSTRING ${DEPS} 0 3 fox)
   if(WERROR AND NOT ${fox} STREQUAL "FoX")
      message("Adding Werror flag to ${DEPS} (fox = ${fox})")
-     target_compile_options(${DEPS} PRIVATE -Werror)
+     target_compile_options(${DEPS} PRIVATE -Werror --warn-no-unused-dummy-argument)
   endif()
 
   install(TARGETS ${DEPS}