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Low Water Pressure at One Tap Only

If the rest of the house is fine, you almost certainly do not need a plumber. Four things cause this, and three of them cost nothing to fix.

Pair of red-handled shut-off valves feeding braided flexible connectors

PressureTrace is a referral service, not a plumbing contractor. We connect homeowners with independent contractors. Contractors are required to hold whatever credential their state or municipality demands. Every state page sets out who licenses plumbers there and where to check, so you can confirm before work begins. We do not perform plumbing work, we do not set prices, and we never charge homeowners anything — the contractors in our network pay us when we route them a call.

We would rather tell you this plainly than route you a call you did not need. When one fixture is weak and everything else is normal, the supply into the property is fine by definition — the restriction is at that fixture.

In order of likelihood

The aerator

The small screen in the end of the spout catches grit and scale. It is the single most common cause and it is free to fix. Unscrew it, soak it, refit it.

The fixture shut-off

Under the sink, or behind the toilet, there is a small valve for that fixture alone. If someone has worked on it recently it may not be fully open. Turn it counter-clockwise until it stops.

Hand holding an old shower head with its holes closed up by hard scale

The cartridge or the supply hose

On a mixer tap a worn cartridge restricts flow, often on one temperature only. Braided supply hoses can also kink behind a vanity where you cannot see them.

Only the hot side

If cold is strong and hot is weak at every fixture, that is not a fixture problem at all — it points at the water heater or its shut-off. That has its own page.

Hand holding an aerator unscrewed from the end of a tap

When it is worth calling after all

If you have cleaned the aerator, opened the valve fully and the fixture is still weak, the restriction is in the branch pipe feeding it. That is inside the wall, and it is a contractor's job.