diff --git a/src/cow_qs.erl b/src/cow_qs.erl
index 2eb52b8..dff840a 100644
--- a/src/cow_qs.erl
+++ b/src/cow_qs.erl
@@ -13,6 +13,7 @@
 %% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 -module(cow_qs).
+-dialyzer(no_improper_lists).
 
 -export([parse_qs/1]).
 -export([qs/1]).
diff --git a/src/cow_uri.erl b/src/cow_uri.erl
index 790d7de..1864139 100644
--- a/src/cow_uri.erl
+++ b/src/cow_uri.erl
@@ -13,6 +13,7 @@
 %% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 -module(cow_uri).
+-dialyzer(no_improper_lists).
 
 -export([urldecode/1]).
 -export([urlencode/1]).