What To Do When You Lose Water Pressure In Your Home
Turning on the shower and getting a weak trickle instead of a decent stream is frustrating. But low water pressure isn't just an inconvenience. It's often a symptom of something worth diagnosing. The fix might be simple, or it might point to a bigger problem in your plumbing system. Here's how to work through it.
Key takeaways:
Start by determining whether pressure loss is at one fixture or throughout the whole house. The cause and the fix are different for each.
Clogged aerators and showerheads are the most common cause of single-fixture pressure loss. Maricopa County's hard water (12 to 18 grains per gallon) makes mineral buildup especially likely.
For whole-house pressure loss, check the main shut-off and call your water utility before assuming the problem is inside your home.
A failing pressure reducing valve is a common cause of whole-house pressure drops in East Valley homes. Testing and replacement require a licensed plumber.
A moving meter with no fixtures running points to a leak somewhere in the system.
Aerator cleaning and valve checks are reasonable DIY steps. PRV replacement, leak tracing, and anything involving the main supply line should be handled by a professional.
1. Figure Out If It's One Fixture or the Whole House
The first thing to determine is whether the pressure loss is isolated or widespread. Turn on faucets in different parts of the house. Check the kitchen, a bathroom on the other side of the home, and an outdoor hose bib if you have one.
If pressure is low at just one fixture, the problem is almost certainly local to that fixture. If it's low everywhere, the cause is somewhere upstream in the system and the list of suspects changes considerably.
2. Low Pressure at One Fixture: Start Here
Clogged aerator or showerhead. In Maricopa County, with water hardness running 12 to 18 grains per gallon, mineral scale builds up fast. The aerator screen on a faucet and the nozzles on a showerhead are common collection points. Unscrew the aerator, rinse it out, and soak it in white vinegar for 20 to 30 minutes. Do the same with a removable showerhead. This is the most common cause of single-fixture pressure loss and the easiest fix.
Partially closed supply valve. Under every sink and behind every toilet is a shut-off valve. If one was recently serviced or bumped, it may not be fully open. Check that the valve handle is parallel to the pipe for a ball valve, or fully counterclockwise for a gate valve.
Failing fixture cartridge or valve. Inside faucets and shower valves, cartridges wear out over time and can restrict flow. If cleaning the aerator doesn't help, the cartridge may need replacing. This is a manageable DIY job for a straightforward faucet but gets complicated quickly in a shower valve. When in doubt, call a plumber.
3. Whole-House Pressure Loss: Likely Causes
Check the main shut-off first. If anyone recently worked on the plumbing or shut off the main valve, confirm it was reopened fully. A partially closed main valve will drop pressure throughout the house.
Call your water utility. Before assuming the problem is inside your home, call your municipal water provider or check their website for service alerts. A main break or supply issue in your area will affect pressure at the meter, and there's nothing to do on your end but wait.
Pressure reducing valve (PRV). Most East Valley homes have a PRV installed where the main line enters the house. It's designed to keep incoming pressure in a safe range. When a PRV fails or goes out of adjustment, pressure can drop noticeably throughout the home. Testing the PRV requires a pressure gauge at an outdoor hose bib. If pressure reads below 50 PSI and there are no municipal issues, the PRV is a likely cause. Replacing a PRV is a job for a licensed plumber.
A leak somewhere in the system. A pipe leaking inside a wall, under a slab, or in the yard can pull enough flow to reduce pressure noticeably. Watch your water meter when no fixtures are running. If the dial is moving, water is going somewhere it shouldn't be. A plumber can locate the source and confirm the extent of the damage.
4. What Not to Try on Your Own
Aerator cleaning and checking shut-off valves are reasonable homeowner steps. Beyond that, most causes of whole-house pressure loss involve components or conditions that require a professional to diagnose correctly.
PRV replacement involves working at the main supply line and often requires draining the system. Attempting it without the right tools or experience can make things worse. Leak tracing inside walls or under a slab requires specialized equipment and carries real risk of unnecessary damage if done blindly. A licensed plumber has the tools and experience to find the problem without tearing into areas that don't need to be touched.
Getting a pressure reading with a gauge at the hose bib is useful information to pass along when you call, but the repair itself is best left to a professional.
When to Call a Plumber
Call a plumber if pressure is low throughout the house and the municipal supply is confirmed fine, if your pressure gauge reads below 50 PSI, if you suspect a PRV failure, or if your meter is running with no fixtures in use. A plumber can test pressure at multiple points, assess the PRV, and determine whether a leak is involved.
Superstition Plumbing has been serving Mesa and the East Valley for 45 years. If you're dealing with low water pressure and aren't sure where it's coming from, our family-owned team can track it down and fix it right. Serving Mesa, Gilbert, Chandler, Queen Creek, and surrounding communities.
