Low water pressure — start with one question
Is it every fixture, or just one? One fixture points to a clogged aerator or cartridge — a cheap clean or swap. Whole-house points to the main shutoff not fully open, a failing pressure-reducing valve, or (if it dropped suddenly and you hear running water) a hidden leak. Hot-only low pressure points back to the water heater. Work that fork below.
One fixture: usually a two-minute fix
Unscrew the faucet aerator and rinse out the debris; soak it in vinegar if it's scaled. For a showerhead, do the same. If only hot or only cold is weak at that fixture, the supply valve under it may be half-closed, or the faucet cartridge is clogged.
Whole house: check these in order
Confirm the main shutoff valve is fully open. If you have a pressure-reducing valve (PRV) where the main enters, a failing one drops pressure house-wide and needs replacing. A sudden whole-house drop with the sound of running water, a warm spot on the floor, or a jump in your water bill can mean a hidden leak — treat that as urgent and see the shut-off-the-main page.
When to call a professional
- • A sudden whole-house drop with signs of a leak — shut the main and get a plumber.
- • A failing pressure-reducing valve, or low pressure that persists after cleaning fixtures.
Common questions
- Why is only my hot water pressure low?
- Sediment in the water heater or a partly closed valve on the hot side. Flushing the heater and checking the valve are the first steps.
- My whole house dropped suddenly — is that bad?
- It can be. A sudden drop with running-water sounds or a wet spot may be a burst or hidden leak — shut off the main and investigate. See the water-leak page.