I was replacing a toilet fill valve last night, and after it was all done, I noticed the following item sitting in the basin I had placed underneath:

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It looks unused, so I'm assuming it fell out of the new fill valve, but I can't figure out what it is. Presumably it's some kind of aerator, but why would a fill valve need one? Everything seems to be working fine without it. Can someone here identify what this thing is?

  • what are the dimemsions of this part? Commented Mar 8, 2014 at 10:25
  • @shirlockhomes - about 1/2 inch diameter.
    – Dave
    Commented Mar 9, 2014 at 2:12

1 Answer 1


Looks like an aerator or flow restrictor. My guess is flow restrictor. Probably was a handy place to toss it, or keep it for later use if need be, by whomever removed it. Or maybe it just fell in after removal and nobody could spot it to throw it away properly.

  • 1
    Might reduce the shower-scald <-> toilet flush connection, if it fits on the new toilet valve somewhere.
    – Ecnerwal
    Commented Mar 8, 2014 at 3:49
  • Never seen one for a toilet, that is adjusted by a screw on the float mechanism. Shower anti-scald is set by the mixer valve, at least the ones I seen. I installed two myself in the past 6 months. I will bet if the aerator for the sink in the same bath is taken apart, Dave will find it fits. But it is still a guess
    – Jack
    Commented Mar 8, 2014 at 5:14
  • Now knowing it is about 1/2 inch in diameter, I think it is an inline flow restrictor that was installed in the base of the ballcock assembly. The purpose would be to slow the flow of water in areas of high pressure that could act like a water hammer on the shut off valve at the top of the unit. I bit of a guess without the make and model of the unit installed so we could look it up. Commented Mar 9, 2014 at 11:17
  • @shirlockhomes - The brand name is "Aqua Plumb" - here is a description: imgur.com/6dcjEGR
    – Dave
    Commented Mar 9, 2014 at 12:51
  • Never heard of an inline restrictor for a toilet, won't need one for gallon restriction, and code may now need one for toilets, but according to what I understood hammer arrestors were only needed on fixtures and appliances that shut the water off quickly, like washing machines and dishwashers that have a solenoid. Anything that shut the water off gradually, did not need it. The shape of it is what makes me think it belongs in a faucet. It is not completely cylindrical. Typically, the part this fit into in a faucet has the same slightly rounded profile, although the aerator usually sets there.
    – Jack
    Commented Mar 9, 2014 at 13:00

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