enter image description hereA few weeks back I started seeing water dripping from my water heater. Called in someone who said my home water pressure was 130 and causing the valve to “leak”. He said my water pressure regulator coming into the house was bad and quote $750 to replace. So i checked it myself and the pressure was around 120-130. So I adjusted down to 90. But now all my grass has died in areas because there is very little pressure going to the sprinklers. *(but resolved the heater leak). Can pressure regulators give an incorrect pressure? I’ve got very little pressure but it is showing 100 psi. I dont want to crank it up too high in risk of pipe damage. Ideas on what I should do next?

EDIT/Update. Bought another gauge. Same reading, so not the gauge. Here is the bizarre thing. I had my son watch the meter as I adjusted the regulator upward (more pressure). The gauge didn’t change, still reads 120, but the sprinklers are “normal” now.

EDIT/Update Added a new regulator. Everything works fine now. The really strange thing is how I was reading 120 PSI outside but my irrigation system was not working. But when I replaced my regulator to now provide 50 PSI, my irrigation system is back to normal. See the image - I dot have ONE line coming in to the regulator after which it splits - one to the house and one to the irrigation system…

enter image description here

  • Clearly false reading on the meter. If you had 130 PSI, you will know if you open any faucet, or might have pipes bursting.
    – Traveler
    Aug 13, 2022 at 18:17
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    Please describe how you checked your water pressure. Is there a pressure gauge somewhere in your house?
    – MTA
    Aug 13, 2022 at 18:17
  • Water pipes/systems(home) do not like pressures above ~80 pounds. Would get an independent pressure gauge you can attached to an outside faucet(garden).
    – crip659
    Aug 13, 2022 at 18:17
  • Thanks all. I used a pressure meter that screws onto the outside of the house. Aug 13, 2022 at 18:27
  • Describe the water dripping from water heater ? where ?, I had that once and it was the corroded water heater goody, somewhere in the middle.
    – Traveler
    Aug 13, 2022 at 18:43

1 Answer 1


Pressure regulators don't give any reading, that's done by pressure gauges. Those can (rather rarely, though with cheaply made ones perhaps more often) go bad, as can the regulators (which typically cost under $100 for household size if you swap it yourself.) Even cheaper and less plumbing required is rebuilding the regulator in place, by replacing the internal parts only.

It's not clear (as you've given few details) how this pressure regulator (aka pressure reducing valve - same thing) relates to your irrigation. In most cases irrigation has a further reduction in pressure from household pressure. Irrigation typically is a very high flow rate load, and it might be affected by the need for simple maintenance (rather than replacement) of the filter screens commonly built into home water pressure regulators. You should check the pressure before and after the pressure regulators with the irrigation system turned on (and off) to see if the pressure drops significantly with the system on, and then look for directions on how to clean your filter screens or replace the guts of your pressure regulator, if needed.

You'll also want to re-check if the pressure has stayed where you reset it to. NOT having permanently mounted (but valved off for maintenance) pressure gauges before and after a pressure regulator is a poor place to save money. At minimum, put in boiler drains with hose threads on both sides so you can attach one of the portable gauges as you used outside right there. But really, having both gauges readable at the same time is most convenient, and makes finding problems much easier.

So, for a short list without replumbing anything yet:

  • check the pressure to see if it stayed at 90 as set, or changed again already. Not staying where set is a sign than you need to rebuild or replace the pressure regulator.
  • Now turn on the irrigation and check the pressure (of the house, via the same hose bibb location.) Does it stay where set, or drop precipitously?
  • Since you mention low irrigation pressure, find or make a place to attach your pressure gauge to the water pipes serving your sprinkler heads (or other water-distributing devices, such as drip irrigation) and check the pressure there. In most system types, 30 PSI is a typical value and involves an additional pressure regulator just for the irrigation.
  • Turn off the irrigation, and run water in the house (run the dishwasher or laundry washer, or run the tub/shower) - does the pressure remain as set, or not?

If the pressure with water flowing is not where set, or close (5-10 PSI lower), The regulator is not flowing well, which might mean it has clogged filter screens, or it might be a different indication that it needs to be rebuilt. Or, there may be a different clogged filter elsewhere in the system, since you are not measuring right at the regulator.

  • There was a direct change in irrigation water pressure (less) after I adjusted the home pressure (less). And yes. My irrigation line feeds off the line after my pressure regulator. So reducing my home pressure will reduce my irrigation pressure Aug 13, 2022 at 18:38
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    That's still devoid of detail. Your irrigation needs 130 PSI to function? Connect it before the regulator serving the rest of the house. 90 PSI is already way too much for most irrigation components. 30 PSI is far more typical. Does your irrigation system have a pressure regulator of its own? Have you checked it? What is the irrigation system pressure at the sprinkler feed?
    – Ecnerwal
    Aug 13, 2022 at 18:42
  • +1 for very detailed/informative answer
    – Traveler
    Aug 13, 2022 at 19:21
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    "still reads 120" does not sound like it held 90. If the house pressure does not change when you adjust the regulator, but the sprinklers do, I have to wonder if you've got the house and irrigation regulators mixed up (because I can't see the piping, so if I go on what you just said happened, I have to wonder if you have been adjusting the regulator for the sprinklers, and not the regulator for the household pressure. You can see the piping, so perhaps that's not the case and you're sure of it, but the behavior just reported is entirely consistent with that being the case...)
    – Ecnerwal
    Aug 14, 2022 at 12:26
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    The bad regulator could have been restricting the volume, while failing to regulate the pressure. For example, if the regulator valve froze in a just-slightly-open position, then it would allow full pressure through but not allow enough volume through to satisfy the sprinklers.
    – longneck
    Aug 17, 2022 at 17:49

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