diff --git a/app/services/word_watcher.rb b/app/services/word_watcher.rb
index 4f5b516b624..b6b136d00c5 100644
--- a/app/services/word_watcher.rb
+++ b/app/services/word_watcher.rb
@@ -2,6 +2,7 @@
 
 class WordWatcher
   REPLACEMENT_LETTER ||= CGI.unescape_html("■")
+  CACHE_VERSION = 2
 
   def initialize(raw)
     @raw = raw
@@ -105,7 +106,7 @@ class WordWatcher
   end
 
   def self.word_matcher_regexp_key(action)
-    "watched-words-list:#{action}"
+    "watched-words-list:v#{CACHE_VERSION}:#{action}"
   end
 
   def self.censor(html)