Said It Here

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 people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    closing the main ball valve
  2. 2
    replacing the unit with another brand new one
  3. 3
    Replacing the faulty pressure-reducing valve yourself using two wrenches and plumbing tape
  4. 4
    Checking water pressure at different hose bibs or the water heater drain
  5. 5
    Hiring a licensed plumber to inspect and replace the valve

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/Plumbing1 person · September 2026

“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 ↗

yin83 · r/Plumbing · 2 upvotes
r/HomeImprovement1 person · September 2026

“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 ↗

infinibee2 · r/HomeImprovement · 1 upvotes

Where this came up

People with this problem also raised