plumbing part

What is the part above the ball valve? What does it do?

  • 2
    Looks like a pressure regulator.
    – Jon Custer
    Mar 19, 2022 at 3:26
  • 1
    As it has a piece prior to the regulator I would bet a check valve and pressure regulator that makes a good system having both.
    – Ed Beal
    Mar 19, 2022 at 5:11
  • Might be a sintered filter rather than a check valve. Also, @JonCuster. put that in the answer box, it is one, and correct.
    – Ecnerwal
    Mar 19, 2022 at 17:12

1 Answer 1


Looking at, say, Home Depot (no relation, just a handy link) one sees pretty much the exact same thing.

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The data sheet clearly indicates that the lower ‘bump’ is for the inlet strainer, the bell shaped bit above is the pressure regulator.

I have one on the inlet to my house. I live directly down hill from a large city water tank, and the water pressure on a hose bib at the far corner of the house from the supply pipe was over 100 psi, well above the max pressure rating of, well, anything in the house. Adjusting the screw at the right of the picture adjusts the outlet pressure to something more reasonable.

  • 1
    What boggles me (I've had wells nearly all the time, nearly always have gauges) is that these are frequently installed without the pressure gauges I'd consider pretty much required for sensible operations - minimum one after, better one before and one after.
    – Ecnerwal
    Mar 19, 2022 at 18:37
  • 1
    Depends on the space. Mine is tucked into a wall near the garage where the water comes in - no basement, no real space. A gauge on a hose bib works fine to set and check occasionally…
    – Jon Custer
    Mar 19, 2022 at 18:43

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