Pressure as the hidden cause

The pressure arriving from the street varies by neighborhood and elevation. Many homes have a pressure-reducing valve, often called a PRV or regulator, near where the line enters the house. It lowers incoming pressure to a level household plumbing is designed for.

Regulators wear out. When one fails open, full street pressure reaches every fixture, and burst hoses, dripping relief valves and banging pipes start showing up together. Some homes never had a regulator at all.

Signs pressure may be too high

  • Several supply lines or washer hoses have failed in a short span
  • The water heater relief valve drips or discharges
  • Pipes bang when a washer or dishwasher valve closes
  • Faucets spray hard and toilets run or hiss after filling
  • A regulator bell near the shutoff hums or leaks
  • Pressure seems higher at night when neighborhood demand drops

How a plumber checks and corrects pressure

  1. Measure static pressure.A gauge on a hose bib or laundry valve reads pressure with no water running. Some plumbers leave a gauge with a tattletale needle to catch spikes over a day.
  2. Inspect the regulator.If there is one, they check whether it is holding its setting, leaking or failed.
  3. Adjust or replace.Some regulators can be adjusted. A worn one is replaced, and a home without one may need one installed.
  4. Check thermal expansion.With a regulator in place, heated water has nowhere to expand. An expansion tank at the water heater is commonly used to absorb that pressure.

Terms you will hear

Static pressure
Pressure in the pipes when no water is flowing.
PRV / regulator
Pressure-reducing valve that lowers incoming street pressure to a set level.
Thermal expansion
The increase in volume and pressure as water heats in a closed system.
Expansion tank
A small tank near the water heater with an air cushion that absorbs expansion.
Water hammer
A pressure shock and banging sound when flowing water stops suddenly.
  1. What is my static pressure, and did it spike during the test?
  2. Do I have a regulator, and is it working?
  3. Do I need an expansion tank with the regulator?
  4. Which hoses and connectors were stressed and should be replaced now?
  5. Would water hammer arrestors help with the banging?

Common questions

Can I check my own water pressure?

Yes. Inexpensive gauges thread onto a hose bib. Read it with all water off inside. If it seems high, have a plumber confirm and check the regulator.

Does the city control my house pressure?

The utility delivers water to the meter. Pressure regulation inside your property is generally the homeowner's responsibility; check with the city if street pressure seems unusual.

How long do regulators last?

It varies with water quality and pressure. Hard water and debris can wear them faster. If yours is old and pressure seems high, have it tested.

General information for Fullerton, not a quote or professional advice. In an emergency, call 911.