Low Water Pressure in House: 7 Causes and How Plumbers Fix It
Low water pressure in the whole house is frustrating, and in California homes it is often a warning sign of a bigger problem in the pipes. Here is how we diagnose it.
1. A partially closed main valve
Check the main shutoff near the street and the one where the line enters the house. After any repair, these are sometimes left partly closed.
2. A failing pressure regulator
Most California homes have a pressure-reducing valve (PRV). When it fails, pressure can drop or spike. Replacement is a quick job.
3. Corroded galvanized pipes
Homes built before the 1970s often still have galvanized steel pipe that closes up with rust from the inside. The permanent fix is a whole-house repipe.
4. A hidden leak
A leak in the main line or under the slab robs pressure from every fixture. Our leak detection service finds it without digging.
5. Main water line damage
Roots, shifting soil and old materials damage service lines. Water line repair or replacement restores full flow.
6. Clogged aerators and cartridges
If only one faucet is weak, it is usually mineral buildup — simple faucet repair.
7. Municipal supply issues
Ask neighbors. If the whole street is low, call the water district first.
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