What Causes Low Water Pressure — and How to Fix It

Low water pressure has many possible causes. The right fix depends on whether it's one fixture, one bathroom, or the whole house.

One faucet only

Almost always a clogged aerator or cartridge. Clean or replace — quick fix.

One bathroom only

Often a partially closed shut-off valve or a corroded supply line. Sometimes a section of galvanized pipe still in place.

Whole house cold water

Check the main shut-off, then the pressure regulator (PRV). Failed PRVs are one of the most common whole-house pressure issues.

Whole house hot water only

Sediment in the water heater tank or scale in a tankless heat exchanger. Both are fixable with service.

Sudden loss with no warning

Check for leaks, a stuck-closed valve, or a municipal issue by asking a neighbour.