Why Your Water Pressure Is Low and What to Do About It

Low water pressure is one of those problems that starts as an annoyance — a shower that takes twice as long, a faucet that dribbles — and ends as a symptom of something more serious. The diagnostic path depends on one key question: is the pressure low everywhere in the house, or just at one fixture?

Low Pressure at One Fixture: Start Here

If only one faucet or showerhead has weak flow, the problem is almost always local. Tucson's hard water clogs aerators and showerhead holes with mineral deposits over time. Unscrew the aerator (the small screen at the tip of the faucet spout), soak it in white vinegar for an hour, and reinstall. Do the same with a showerhead. If flow returns, that was your answer.

• →Clogged aerator — soak in vinegar, clear the screen
• →Clogged showerhead — vinegar soak or replacement
• →Partially closed angle stop under the sink
• →Failing cartridge inside the faucet body

Low Pressure Throughout the Home: Five Causes

1. Pressure Regulating Valve (PRV) Failure

Most Tucson homes have a PRV on the main supply line near where it enters the house — it prevents the street pressure (which can run 80–100 psi) from damaging your fixtures. PRVs last 10–15 years and when they fail, they often fail closed, dropping your household pressure to 30 psi or lower. A plumber can test and replace a PRV in an hour.

2. Partially Closed Main Shutoff

After any repair or service that required shutting off the main, the valve may not have been reopened fully. Check the main shutoff — it should be fully open (parallel to the pipe for ball valves, fully counterclockwise for gate valves).

3. Scale Buildup in Older Galvanized Pipes

Tucson homes built before 1975 often have galvanized steel supply pipes. These corrode from the inside out, gradually narrowing the interior diameter over decades. If your home is older and pressure has been declining slowly for years, galvanized pipe is the likely culprit. Repiping with copper or PEX is the lasting solution.

4. A Hidden Leak

If water is escaping through a crack or failed joint in your supply system, pressure drops before reaching your fixtures. A sudden pressure drop — especially accompanied by higher water bills — points to a leak.

5. Water Utility Issues

Check with your neighbors. If everyone on the street has low pressure, Tucson Water is the source and the issue will resolve when they repair it. If it is only your home, the problem is inside your property.