diff --git a/conf.py b/conf.py
index 40372a3..ade5f52 100644
--- a/conf.py
+++ b/conf.py
@@ -45,7 +45,7 @@ def get_version():
 # needs_sphinx = '1.0'
 
 # make all warnings errors
-warning_is_error = False
+warning_is_error = True
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom