Why does water pressure keep creeping up with a new PRV?
Even after installing a brand new pressure reducing valve, pressure can still creep up to full utility levels when water is not flowing. This happens because debris or a bad seat inside the valve prevents it from sealing completely, which causes the house pressure to slowly match the incoming supply and can lead to vibrating or humming noises in the plumbing.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- This comes up 17.4× more often in r/Plumbing than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
Why does water pressure keep creeping up with a new PRV?
- 1closing the main ball valveDid this help you?
- 2replacing the unit with another brand new oneDid this help you?
- 3Replacing the faulty pressure-reducing valve yourself using two wrenches and plumbing tapeDid this help you?
- 4Checking water pressure at different hose bibs or the water heater drainDid this help you?
- 5Hiring a licensed plumber to inspect and replace the valveDid this help you?
- 6Looking for erosion on the brass where the seals make contactDid this help you?
- 7Using a full rebuild kit instead of just a rubber repair kitDid this help you?
- 8Replacing the pressure reducing valve (PRV)Did this help you?
- 9Checking or installing a thermal expansion tankDid this help you?
- 10Turning the adjustment bolt in the opposite direction of standard instructions to achieve the desired pressure.Did this help you?
- 11Opening the drywall to access and replace the PRVDid this help you?
- 12Buy a generic glycerin-filled pressure gauge with standard 1/4" NPT threads instead of the name-brand version.Did this help you?
- 13Replace the entire regulator unit and install a separate pressure gauge next to it.Did this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“trying to diagnose a vibrating/humming noise in my home’s plumbing.”source ↗
“the PRV appears to be providing little or no meaningful pressure reduction.”source ↗
“Inspector mentioned the water pressure is at like 80.. I want to fix this before I ruin something.”source ↗
“When I closed the system back up after replacing the rear o-ring, piston o-ring and diaphragm. I regained the ability control the dynamic pressure but the static pressure is still over the value rating and equal to street pressure.”source ↗
“My question is did I do something wrong during the rebuild or did the valve likely fail due to internal erosion?”source ↗
“Water pressure went up to 120 earlier today. I replaced the PRV with a new one.”source ↗
“Went to take a shower. Went back out to check and pressure went back up to 130 when I was in shower. What should I look at next?”source ↗
“Turned the bolt counterclockwise on the PRV like you're supposed to, and it went UP. Like...way up. Was confused.”source ↗
“So then I turned it CLOCK WISE...and it went down. Sooo...I kept on doing that until I ended up at 50. Heh. BUT...this appears to be pretty universally NOT correct, so I'm wondering...what the hell? Does it need to be replaced?”source ↗
“I have a five-year-old Apollo water pressure regulator with a gauge. I just realized the gauge is full of water and leaking.”source ↗
“Searching Amazon. I can’t find just the gauge. It seems like I have to buy a whole new water pressure regulator.”source ↗
“I replaced me old PRV with a brand new one, but the pressure is creeping up with no flow (about 0.1psi/min) all the way until it equilibrates at 75psi which is the utility pressure.”source ↗
“When I close the main ball valve the pressure creep stops immediately.”source ↗