Banging pipes and running toilets: checking your water pressure
Quick answer
Test with a hose-bib gauge. California's plumbing code calls for a pressure regulator when street pressure is over 80 psi. High pressure wears out toilets, faucets and hoses early.
Monterey Park sits on a mix of flat streets and hills, and homes on a slope can sit at quite different elevations from each other and from the water mains that serve them. Water pressure at a house depends partly on that elevation and on how the water system is arranged.
Some homes see pressure on the high side, and high pressure is hard on everything connected to your plumbing.
This guide covers the signs of high pressure, how to check it yourself, what a pressure regulator does, and what our visit involves.
Signs your pressure may be too high
- Pipes that bang or thump when a faucet or washing machine valve shuts off quickly
- Toilets that run or refill on their own
- Faucets that drip soon after being repaired
- A strong blast from faucets even when barely opened
- Washing machine or dishwasher hoses failing early
- A water heater relief valve that drips
Why pressure matters
Most fixtures and appliances are designed for moderate household pressure. California's plumbing code calls for a pressure regulator when street pressure exceeds 80 psi, and many plumbers aim for something in the 50 to 70 psi range for everyday use.
Above that, fill valves, cartridges, hoses and seals all wear faster, and sudden valve closures create shock waves in the pipes, known as water hammer.
Low pressure is a different problem with different causes, such as corroded galvanized pipes, a partly closed valve or a failing regulator.
Check your pressure yourself
A water pressure gauge that screws onto a hose bib is inexpensive and easy to use. Attach it to an outdoor faucet near where water enters the house, make sure no water is running inside, and open the faucet fully. Read the gauge.
What a pressure regulator does
A pressure reducing valve, or PRV, is a bell-shaped brass valve usually installed on the main water line where it enters the house, often near the main shutoff. It reduces street pressure to a steady, set level inside the house. Regulators wear out over time, often after many years, and a failing one can let pressure creep up or drop.
Many homes have one; some older homes do not. If you are not sure, look along the water line near the front hose bib or where the pipe comes out of the ground.
Main shutoffs on hillside lots
On sloped lots, the main shutoff can be in an unexpected place: down by the street, under a deck, or tucked behind landscaping. Find yours before you need it. Old gate valves with round handles often seize or fail to close fully after years without being turned. A quarter-turn ball valve is far more reliable in an emergency.
When to call us
- Your gauge reads over 80 psi, or pressure is high and you see the symptoms above
- An existing regulator is leaking, noisy or no longer controlling pressure
- The main shutoff is stuck, leaking or hard to reach
- Fixture shutoffs under sinks and behind toilets do not close
- Toilets run or faucets drip repeatedly after repairs
Checking the regulator yourself
A hose-thread pressure gauge costs a few dollars at any hardware store. Screw it onto the hose bib closest to where the water enters the house, open the bib fully, and read it with no other fixtures running. Then check again late at night, when neighborhood demand drops and pressure tends to peak.
If either reading is over 80 psi, or the needle creeps upward over a few minutes, the regulator is worth a closer look.
What our pressure and shutoff visit involves
We test pressure with a gauge at an outdoor faucet and confirm whether there is a regulator. If the regulator is failing, we replace it with a correctly sized valve, set it to an appropriate pressure, and check the result at the gauge. If you have no regulator and pressure is high, we install one at the main line.
We also look at the main shutoff and replace an old gate valve with a ball valve if it is stuck or leaking, and check fixture shutoffs inside the house. Afterward, we test pressure again and check for leaks. Our shutoff valves and pressure page has more.
Fixing the damage high pressure left behind
High pressure leaves a trail: running toilets, dripping faucets, worn hoses. Once pressure is under control, those repairs last longer. We can replace fill valves and flappers (toilet repair), faucet cartridges (faucets and sinks), and appliance supply hoses at the same visit.
Water hammer
If pipes still bang after pressure is corrected, the cause may be quick-closing valves in washing machines and dishwashers. Water hammer arrestors installed at those connections absorb the shock. Loose pipes under the house that knock against framing can be secured with clamps where we can reach them.
A yearly check
Test your water pressure once a year with a gauge, and exercise your main shutoff by turning it closed and open so it does not seize. Keep the regulator area clear so it can be reached. Simple habits like these prevent many of the leaks we are called for.
Text a photo of your main line, the regulator if you have one, and your gauge reading to (626) 684-3505.
Pressure checks on the north side of the city often end with dumplings at Mama Lu's Dumpling House, an easy stop between calls.
Want us to handle it?
Call or text (626) 684-3505, Mon–Sat, 8:30 AM–7 PM. Send a photo and we will give you an upfront quote.
Call or text (626) 684-3505