Why Is My Water Pressure Low? Common Causes And Fixes

Low water pressure is one of the most common complaints we hear from homeowners in North County San Diego. It makes showers weak, dishwashers slow, and irrigation ineffective. More importantly, it is often a sign that something in your plumbing system needs attention.

First, check whether the pressure is low throughout the whole house or just at one fixture. If it is isolated — say, just the kitchen faucet — the aerator is probably clogged with mineral deposits. Unscrew the aerator, soak it in vinegar, and reinstall it. Problem solved.

If pressure is low throughout the house, the cause is usually one of the following: a partially closed main shut-off valve, a failing pressure regulator (PRV), significant mineral buildup inside older galvanized pipes, or a leak somewhere in the supply system.

The pressure regulator is a bell-shaped device typically found where the main supply line enters the house. Most homes in the area are set between 50–65 PSI. If yours has drifted below 40 PSI or failed entirely, the fix is a straightforward PRV replacement — usually a few hundred dollars and completed in under two hours.

Galvanized steel pipes — common in homes built before 1970 — corrode from the inside, progressively reducing flow over decades. If your home still has galvanized supply pipes and pressure has been declining for years, a whole-house repipe may be the most cost-effective long-term solution.

If you suspect a leak, look for unexplained wet spots, a water meter that does not stop moving when all fixtures are off, or a rising water bill without a usage change.

For a professional pressure test and diagnosis, call 211 Plumbing & Drains at 760-557-9413. We serve North County San Diego and can usually be out same-day.