diff --git a/consul/base.py b/consul/base.py
index 313d0d5..2e37cab 100755
--- a/consul/base.py
+++ b/consul/base.py
@@ -399,11 +399,11 @@ def __init__(self,
         self.service = service
         self.health_client = health_client
         self.passing = passing
-        self.dc = dc
+        self.dc = dc.lower()
         self.index, service_health = health_client.service(
-            service=service,
-            passing=passing,
-            dc=dc,
+            service=self.service,
+            passing=self.passing,
+            dc=self.dc,
         )
         self.cache = {self.service: service_health}