diff --git a/lib/spack/spack/build_environment.py b/lib/spack/spack/build_environment.py
index ae93d10d7b..68f1a11481 100644
--- a/lib/spack/spack/build_environment.py
+++ b/lib/spack/spack/build_environment.py
@@ -691,9 +691,9 @@ def setup_package(pkg, dirty):
         dpkg.setup_dependent_environment(spack_env, run_env, spec)
 
     if (not dirty) and (not spack_env.is_unset('CPATH')):
-        tty.warn("A dependency has updated CPATH, this may lead pkg-config"
-                 " to assume that the package is part of the system"
-                 " includes and omit it when invoked with '--cflags'.")
+        tty.debug("A dependency has updated CPATH, this may lead pkg-config"
+                  " to assume that the package is part of the system"
+                  " includes and omit it when invoked with '--cflags'.")
 
     set_module_variables_for_package(pkg)
     pkg.setup_environment(spack_env, run_env)