My toilet fill valve was starting to act funny so I thought I would replace both the fill valve and the flapper since they are relatively inexpensive. I bought these two:

They each have an adjustment to conserve water.

The fill valve has a roller clamp on the refill tube that goes down the overflow pipe: enter image description here

When this was all the way open, there was a high pressure jet of water going down the overflow pipe, which seems like a waste of water. I cranked this down so that it is now weak stream of water.

The flapper has this thing you can rotate to adjust the volume of the flush. It seems to basically adjust the amount of time the flapper is open: enter image description here

I'm probably overthinking this, but how should adjust these two things together to get good flushing performance and not waste water?

  • Keep in mind water down the overflow tube isn't all wasted, that water does run out the rim continuing to rinse the bowl. Overflow implies waste, but in this case it's also part of the flush cycle.
    – Tyson
    Commented Jan 29, 2017 at 21:03

1 Answer 1


This is a trial and error adjustment. Less water flow means less washing of the bowl for any residue. But bowls vary greatly in shape and volume that also affect their washing characteristics.

Start with extreme limiting and see how it works. Then increase flow if needed. You may want to change only one at a time

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