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How to check your home's water pressure

Updated . By the OakTend team.

Outdoor water spigot with two green garden hoses on a sunlit white wall

You thread an inexpensive pressure gauge onto an outdoor hose bib or the washing machine's cold tap, open the tap fully and read the number.

How often
No agency publishes a schedule. Check once when you move in, and again if a toilet runs on its own, faucets drip or your relief valve weeps.
What you need
Water pressure gauge with hose threads

Why it matters

The plumbing code requires a pressure regulator when the street pressure coming into a house is over 80 psi, because pressure that high is hard on fixtures, water heater valves and appliance hoses. A regulator that has worn out can let high pressure through without anyone noticing.

Steps

  1. Make sure no water is running anywhere in the house.
  2. Screw the gauge onto an outdoor hose bib or the washing machine's cold water tap.
  3. Open the tap all the way and read the gauge.
  4. Compare: a water district's guideline puts normal indoor pressure at 45 to 65 psi, and code caps it at 80 psi.
  5. Close the tap and remove the gauge.
  6. If you have a regulator (often a bell-shaped valve where the main line enters the house), note your reading so you can spot it creeping up later.

When to call a pro

Call a licensed plumber if the reading is over 80 psi, either to install a regulator or to replace a failing one. When a regulator goes in, the code also calls for an expansion tank on the cold water line after it.

Safety

Leave adjusting or replacing a regulator to a plumber, and keep the expansion tank in mind: the code pairs the two.

Go deeper

General information, not professional advice. Your equipment's manual comes first when it says something different.

Sources

More water heater and plumbing