How do I test my home's water pressure?
Buy a water pressure gauge at any hardware store. Make sure no fixtures are running, then screw the gauge onto an outside hose bib and turn the valve on fully. Read the dial. Normal residential pressure is about 50 to 70 PSI. Below 40 PSI is low; common causes are a failing regulator, a partly closed valve, a leak, or old pipe. Above 80 PSI is high enough to damage fixtures and appliances; the California Plumbing Code requires a pressure regulator when street pressure is over 80 PSI.
Step by step: testing water pressure with a gauge
- Buy a gauge: Get a water-pressure test gauge with a female garden-hose thread. Most hardware stores carry them. Pick one with a peak-pressure marker (a red needle that gets pushed up by the highest reading and stays there) so you can catch pressure spikes.
- Find an outdoor hose bib: Use one on the house side of the pressure regulator so you read the pressure your plumbing actually sees. The hose bib right at the main line may be before the regulator and show street pressure, so a hose bib at the back of the house is usually a safer choice. Not sure? Text us a photo.
- Stop all water use inside the house: Don't run any faucets, don't flush, don't let the washing machine or dishwasher run. Pressure rises when nothing is using water, which is what you want to measure.
- Attach and read: Screw the gauge onto the hose bib hand-tight. Turn the bib fully on. Wait a few seconds. Read the needle. Normal: 50-70 PSI. Below 40 PSI is low. Above 80 PSI is too high and risks damage.
- Leave the gauge on for a day: For a complete picture, leave the gauge attached for 24 hours. The peak-pressure marker will show if pressure spikes during the night when nothing is running. Spikes above 80 PSI usually mean thermal expansion from the water heater or a regulator that's wearing out. Thermal expansion is fixed with a properly sized expansion tank, and its air charge has to be set to match your house water pressure before it's installed; we always do that step. Call or text Sweetwater and we'll find out whether it's thermal expansion or the regulator.
- Test at different times: Test in the early morning and late evening. Very different readings can mean your water supplier's pressure swings during the day, or that your regulator is wearing out.
When to call Sweetwater: If your pressure is over 80 PSI, under 40 PSI, or the peak needle shows spikes, call (909) 312-4516 or text (909) 247-6791. We'll find the cause and give you options, whether it's the pressure regulator, the expansion tank, or a leak or restriction in the line.
Serving 24 cities across the Inland Empire.
Chino · Chino Hills · Claremont · Colton · Corona · Diamond Bar · Eastvale · Fontana · Grand Terrace · Highland · La Verne · Loma Linda · Mira Loma · Montclair · Norco · Ontario · Pomona · Rancho Cucamonga · Redlands · Rialto · Riverside · San Bernardino · San Dimas · Upland