I have a single flush toilet that I would like to swap to a dual flush to try save money on water.

This is my current single flush and I’ve seen dual flush kits. Is this a straight forward diy job or is it a lot more complicated than it looks? Will I also need to replace the full valve mechanism?

FYI this is a uk toilet if that makes a difference

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  • 2
    It should be a simple replacement type of job. Believe most dual flush upgrade kits will come with all the parts needed, so just need to turn off the water, remove the old flush, and replace with new. A local plumbing shop should have the correct information and the right kit for your toilet(think they are almost universal).
    – crip659
    Jun 26 at 13:33
  • You will save on water, but eventually you may pay for a plumber to snake out your system. I want a lot of water going down my pipes, carrying all the waste to the main sewer line. Low flow toilets? No thanks! Jun 26 at 13:54
  • @SteveWellens If just liquid, no paper/solids, a full flush is probably not needed. Do agree that any paper/solid waste would want a full power flush.
    – crip659
    Jun 26 at 14:57
  • I'm a disgusting individual and only flush when there's paper/solids.
    – JACK
    Jun 26 at 16:03
  • 1
    @crip659 I doubt a full flush would carry everything out to the main sewer line. And a few half flushes may or may not finish the job. I will always error on the side of wasting a bit of water and never having to call a plumber. Jun 27 at 4:44

2 Answers 2


Well the rules during the last drought on the west coast was if it’s brown flush it down, if it’s yellow let it mellow!

I am surprised I haven’t seen this slogan with the drought in the south west. I agree with crip659 + that the parts normally come in the dual flush kit.

the kits I have installed in the past were 20-30$ and function well although I don’t know how long they last as I installed them for others.

All the instructions came in the kits it was easy even an electrician could do it.

  • That was the slogan during the drought in the mid-70s, too, Ed. It was shortly after that that Mello Yello came out. I've never drunk it. ewww!
    – FreeMan
    Jun 27 at 12:19

As some information that I found out over the weekend. To replace the flush mechanism you'll need to

  1. turn off the water to the cistern at the back of the toilet (and drain the cicstern obviously)
  2. You'll now need to remove the cistern, two screws at the back to attach it to the wall and the nuts underneath to attach it to the bowl
  3. once removed you can unscrew the flush mechanism and replace with the new one
  4. then put the cicstern back on and done.

As others have noted in the comment, sometimes a half flush might not be enough to get all the contents out to the sewers

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