While having my plumber determine what to do about a leak in my water main (city water supply), he mentioned that I should probably replace my house water pressure regulator if it hasn't been replaced in the last five years or so. I don't understand why age matters.

He did a static pressure check and the measurement was 65 PSI. With a faucet open, it dropped to 35 PSI.

We checked the pressure on the landscape plumbing, which is unregulated, and it was 125 PSI, static.

I'm always leery of being upsold beyond what I need. Is there anything to his statement that a regulator over 5 years old should be replaced? (He actually said 3 to 4 years old, I think, which is a red flag for BS, in my opinion.) I think this one is nearly 25 or 30 years old. Does the water pressure test suggest that it needs to be replaced?

If it should be replaced, it should probably be done while the main line is repaired, since it looks like the work will all be around the same section of pipe.

(My water is not very hard. by the way. I never find much in the way of deposits in any repairs I have made. I have replaced short sections of copper pipes a couple of times.)

4 Answers 4


Age matters because the unit has springs inside and the springs can lose tension over time, also your seals can fail.

All of that said - you can take the 5 years thing with a BIG grain of salt. People say the same kinds of things about torsion springs on a garage door. Usage Matters.

With a faucet open OF COURSE your water pressure is going to drop - hey you have running water - the water follows the path of least resistance - it is not running into your gauge any more - but into the drain.

What you are seeing is normal pressure drop with an open faucet. You probably should lower your pressure a little as 85PSI is probably at the high end.

Here is a video on adjusting the water pressure.


125 psi unregulated is excessivly high water pressure. If this is true, it should be verifiable by simply contacting your local water district. as a plumber that tests water pressure regularly in several diffferent counties in northern California, I fear the pressure gauge might be faulty. it should always start at zero, if dropped it will damaged and give a false reading. How ever if your plumbers gauge is working correctly, than you need a new regulator IMEDIATLY! Any time a sink faucet (0.78-2.8gpm) is opened and water pressure drops more than 10psi from static psi you need a new regulator pretty soon. if you are getting a 25 or more pressure drop your regulator its bad and needs to changed now. Those kind of pressure fluctuations will break fixtures and many times burst pipes. A tub spout or hose bib will push 4-8 gpm, and will easily drop 15psi from static pressure. with a bad regulator you will see an exponentially bigger drop. Now if your district is giving you 125psi during peak use hrs, it is very likely that you will go through regulators much quicker (ie 5 years) than a district that is pushing 100psi during peak use hours, which can last 7-15 years.

Every neighborhood will have differing pressures. Distance from your local water district, and elevation play major roles in the pressure in your neighborhood. Water pressure will change through out a 24 hr period. Static testing during peak use hours(day) will be different than low use hrs(night). Ask to see if you plumbers gauge. it be at zero when holding it in your hand. it should be metal and glass, without a plastic lens, a gauge with a plastic lens is not to be trusted. if his gauge checks out, have it changed, he if he didn't explain all this to you, he probably is trying to upsell, but got lucky and was right, You need a new pressure regulator . just make sure you are getting an all brass prv from a plumbing shop, npt a box store like the hd or lowes.

hope this helps and Good luck.

Plumber from Nor Cal

  • I'm a little suspicious of this advice. None of my houses in the UK had a pressure regulator at all. We just used whatever came out of the water company pipes. (Now it may be that English supply water pressure is lower, so a regulator is unnecessary.) Commented Oct 2, 2019 at 8:48
  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know how best to contribute here. Commented Oct 2, 2019 at 13:22

10 years is a little more reasonable - they usually last at least 15 years. He might just be recommending it because if you don't do it now you'll probably forget all about it and it won't be changed until its failure causes problems. The regulators themselves are usually around $40 so it's not that big of an upsell compared to excavating and replacing your main supply line.

125psi unregulated is not abnormal at all*. 65psi regulated is a bit high, but nothing to be overly concerned about unless you notice water hammering or plumbing noise (it might mean you're using more water than you think though, since faucets and showerheads assume 60psi on their flow ratings). Typically they're factory set at 50psi, so this may be a sign of springs losing their tension (or perhaps someone had simply adjusted it for some reason). If you think it's nearing 30yo though, it's well past its life expectancy - I'd replace it while it's on your mind if I were you.

(*) I see you're in drought-prone California, you should probably consider adding a pressure reducer to your unregulated spigot if you have it under any sort of continuous or frequent (> 1/2hr per day) use, as it's likely putting out several times the water that you really need it to.


I realize that it's been two years since you posed the question and you've long since made a decision about what to do, but for the benefit of other people who run across this question, I thought that I would share my opinion on this subject. I just replaced my own regulator which failed sometime in the past year. A year ago I checked the regulator and it was working as it should but when I checked it a couple of months ago the pressure would gradually creep up. This was not related to expansion from the water heater. That pressure regulator was about 30 years old. I have never seen a recommendation that they be replaced nearly that often.

Relating to the pressure check, that type of performance might be ususal or it might indicate failure. If he did not tell you how to tell the difference then I think that he was trying to upsell you. The following information is based on the assumption that you have half-inch pipes and that your house is plumbed in a conventional way. The pressure that shows up in the test can depend on where the pressure guage is and where the faucet is in the plumbing circuit. If there is a long run of half-inch pipe between the pressure regulator and the faucet then when that faucet is running it is expected that the pressure will drop between the pressure regulator and the faucet, especially if the faucet doesn't have any type of flow restricter. This also assumes that the pressure guage is at an equal distance or further downstream from the faucet being tested. The most accurate test would be done using the faucet that is nearest the pressure regulator.

Something else that could cause the observed problem is if the filter screen that is in the pressure regulator is partially clogged and needed to be cleaned. If the plumber didn't mention that to you then it sounds like he was trying to upsell you.

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