Strong water pressure feels great in the shower, but too much of it quietly stresses pipes, joints, and appliances — and shows up as banging 'water hammer.' Here is what causes it and how to fix it.
Written bySteven Lockhart·Reviewed byMiguel Lopez, Owner & Licensed Plumber (CSLB #974600)·Last reviewedJune 2026 · 4 min read
Quick Answer
High water pressure in a house — typically anything above about 80 psi — stresses pipes, joints, fixtures, and appliances, and is a common hidden cause of leaks and short appliance lifespans. It also produces water hammer, the banging or knocking you hear when a valve closes. The fix is usually a pressure regulator (PRV) to bring incoming pressure into a safe range, plus addressing the water hammer itself. This is part of our complete guide to water pressure regulators in West Los Angeles.
What causes high water pressure is usually the municipal supply: city water is often delivered at a higher pressure than a home needs, sometimes to serve hydrants or higher elevations on the same line. Homes near the bottom of a hill or close to a pumping station can see especially high pressure. Without a working pressure regulator, that full pressure reaches your pipes. Thermal expansion from the water heater can spike it further in a closed system. This guide is part of our complete resource on water pressure regulators in West Los Angeles.
High water pressure is household supply pressure above the recommended range (commonly considered over 80 psi), which stresses pipes, fixtures, and appliances and can cause leaks and water hammer.
Water hammer — banging pipes when a faucet or appliance valve shuts — is the shock wave of fast-moving water stopping suddenly. The pipes knocking sound fix depends on the cause: high pressure makes it worse, so a PRV helps; loose pipes amplify it, so securing them helps; and air-chamber or arrestor devices absorb the shock. The table summarizes the causes and fixes.
| Cause | Effect | Fix |
|---|---|---|
| High supply pressure | Harder shock waves | Install/replace PRV |
| Loose pipe runs | Banging against framing | Secure the pipes |
| No/failed arrestors | Shock not absorbed | Add water-hammer arrestors |
| Fast-closing valves | Sudden stops | Arrestors / pressure control |
Too much water pressure does quiet, cumulative damage. It stresses pipe joints and increases the odds of leaks (including pinhole leaks in copper), shortens the life of water heaters, dishwashers, and washing machines, makes faucets and toilet valves wear out and drip sooner, and strains the fittings on braided supply lines — a common burst point. Because the damage is gradual, many homeowners never connect it to pressure until a leak or failure happens. Testing the pressure and installing a PRV is cheap insurance against all of it.
A homeowner hears pipes banging and has replaced two leaking supply lines in a year.
New Pro tests the incoming pressure, finds it well above 80 psi, and installs a pressure regulator set to a safe range.
The banging stops, the strain on pipes and appliances eases, and the recurring supply-line failures end.
The Bottom Line
High water pressure feels powerful but quietly wears out your plumbing and appliances and causes water hammer. The fix is straightforward: test the pressure, and if it is too high, install or replace a PRV to bring it into a safe range. Call any time and we will check yours. More on our water pressure regulator page.
Usually the municipal supply, which is often delivered at higher pressure than a home needs. Homes near the bottom of a hill or a pumping station see more. Without a working pressure regulator, that full pressure reaches your pipes; thermal expansion can spike it further.
It is the banging or knocking you hear when a faucet or appliance valve closes — the shock wave of fast-moving water stopping suddenly. High pressure makes it worse, and loose pipes amplify it.
It depends on the cause: a pressure regulator if pressure is high, securing loose pipe runs, and water-hammer arrestors to absorb the shock. We test the pressure and inspect the cause before recommending the fix.
Yes. It stresses pipe joints and raises leak risk (including copper pinhole leaks), shortens appliance life, wears out faucet and toilet valves, and strains supply-line fittings. The damage is gradual, so it often goes unnoticed until a failure.
Pressure above about 80 psi is generally considered too high for a home, and most plumbing codes require a pressure regulator when supply exceeds that. A simple gauge test tells you where yours sits.
A plumber can measure it with a gauge at a hose bib, or you can use an inexpensive gauge yourself. If it reads above ~80 psi, a pressure regulator is recommended to protect your plumbing.
Written by the New Pro Plumbing content team and reviewed for technical accuracy by Miguel Lopez, owner and California-licensed plumber (CSLB #974600). Pipe lifespans are presented as typical ranges, not guarantees, and any pricing is confirmed in writing before work begins.
What's new: June 2026 — first publication.
We test your pressure and install or replace a PRV to protect your plumbing — flat-rate. Call any time.
