A guide to water pressure
Normal residential water pressure is roughly 30 to 80 psi, with an ideal range of about 40 to 60 psi. Pressure that is too high can damage fixtures, appliances and pipes; pressure that is too low weakens faucet flow and starves washers and dishwashers.
What is water pressure?
Water pressure is the force at which water leaves a faucet — it is different from flow rate. In some systems elevation and gravity create the pressure; cities like Los Angeles rely on pumps and pressure stations.
How to test your home’s water pressure
- Attach an inexpensive pressure gauge to an exterior hose bib, or to the washing machine hose faucet if you have no exterior bib.
- Turn off all fixtures and appliances, open the faucet fully and read the gauge.
- Do not attach the gauge to the water heater drain valve — sediment can clog it and skew the reading.
Common causes of low water pressure
Partially closed valves. Check every shutoff valve on the main supply line, including the water meter valve. Make sure the meter valve handle is parallel to the pipe and the main shutoff is fully open (turn a gate valve fully counterclockwise; align a ball valve lever with the pipe). Broken, leaking or seized valves should be replaced by a professional.
Debris in pipes. Sediment and mineral buildup narrow the pipes. Clean each faucet’s aerator — remove its three parts, rinse and reassemble — then flush the lines by running three or four cold faucets at full force for 2 to 5 minutes.
Corroded pipes. Corrosion builds up inside older galvanized steel pipes, gradually restricting flow and eventually causing holes. The only lasting fix is re-piping, typically with PEX tubing, which is often more cost-effective and easier to install than copper.
Leaking pipes. Look for wet spots or pooling water near pipes. As a temporary fix, shut off the water, dry the pipe and secure a rubber patch with electrical tape and a pipe repair clamp — then call a plumber promptly, since leaks can damage foundations and contaminate drinking water.
Why a water pressure reducing valve (WPRV) matters
A WPRV lowers high incoming municipal pressure to a safer level, protecting your pipes and fixtures. Without one, fluctuating pressure can cause leaks, burst pipes and wasted water. We install and maintain pressure regulators.
Signs of a failing pressure regulator
A failed regulator can cause a sudden spike or a sudden drop in pressure at every fixture. To test, attach a gauge to the outdoor spigot nearest the main or regulator — around 75 psi is typical depending on location. Very low readings may indicate a failed regulator that needs professional replacement.
Plumbing fixtures
Low pressure at every fixture usually points to the supply line or pipes. Low flow at only one or a few fixtures points to the fixtures themselves — clean or replace clogged aerators and fixtures after shutting off the water supply.