Common Causes of Low Water Pressure

Common causes

Low pressure usually comes down to one of these:

• Mineral scale clogging aerators, showerheads, or pipes
• Corroded galvanized pipe narrowing over decades
• A hidden leak diverting water
• A failing pressure regulator
• A partially closed shutoff or main valve

Whole-house vs. single-fixture

If only one fixture is weak, the problem is usually local — a clogged aerator or cartridge. If the whole house is weak, suspect the regulator, the main line, or widespread pipe corrosion. That distinction tells a plumber where to look first.

When to call a plumber

If cleaning aerators doesn’t help, or pressure has dropped across the house, a plumber can test pressure, check the regulator, and inspect for leaks or corroded pipe — and recommend repiping if old galvanized lines are the cause.