Low water pressure: the usual causes

Low pressure at one fixture

If only one faucet or shower is weak, the cause is usually local: a clogged aerator or showerhead full of mineral scale, a partly closed shutoff valve under the sink, or a worn cartridge inside the faucet. Hard water makes aerator buildup common here.

Low pressure everywhere

• A main shutoff valve that is not fully open
• A failing pressure regulator where the line enters the house
• Corroded galvanized supply lines that have narrowed inside
• A leak on the main line between the meter and the house

Check the aerator first. If every fixture is weak, the problem is further back in the system.

When to call a plumber

Cleaning an aerator is a household job. Diagnosing whole-house low pressure means checking the regulator, the main line and the supply pipes, and it is one of the calls we handle regularly. We start with a diagnosis and explain the options before any work starts.

Request a visit for low water-pressure diagnosis.