diff --git a/src/db/pool.cr b/src/db/pool.cr
index df51038..893ccb9 100644
--- a/src/db/pool.cr
+++ b/src/db/pool.cr
@@ -18,6 +18,8 @@ module DB
     # close all resources in the pool
     def close : Nil
       @total.each &.close
+      @total.clear
+      @available.clear
     end
 
     def checkout : T