Low Pressure at Only One Fixture
When only one fixture has weak flow and the rest of the house is normal, the cause is usually local to that fixture or its branch connection. An aerator or showerhead restriction is a good first check, followed by supply valves/lines and the faucet or shower cartridge where applicable. The exact part depends on whether hot, cold, or both sides are affected.
- —Clogged aerator screen (mineral buildup from hard water)
- —Mineral buildup in a showerhead
- —Failing or partially blocked cartridge inside the faucet
- —Partially closed supply valve under the sink
Try This First
Safe, simple steps you can try yourself. If any step feels beyond your comfort level, skip it and continue below.
- 1
Check other fixtures first
Confirm the problem is only at one fixture. Run the kitchen faucet, a bathroom faucet, and an outdoor spigot. If they're all fine, the issue is isolated to the one fixture.
- 2
Remove and clean the aerator
Unscrew the aerator from the end of the faucet spout (hand-tighten usually, or use pliers with a cloth to protect the finish). Remove the screen and soak it in vinegar for 15 minutes to dissolve mineral buildup. Rinse and reinstall.
- 3
Check the supply valve
Under the sink, make sure both hot and cold supply valves are fully open (turn counterclockwise). A partially closed valve restricts flow.
- 4
Clean a clogged showerhead
If it's a shower, unscrew the showerhead and soak it in vinegar overnight, or fill a plastic bag with vinegar and rubber-band it over the showerhead so the face is submerged.
If the problem is resolved
If cleaning the aerator or showerhead restores full flow, the problem was mineral buildup. Soak aerators and showerheads in vinegar every few months to prevent recurrence.
If the problem persists
If cleaning the aerator doesn't help, the cartridge inside the faucet may be failing and restricting flow. Continue below.
Stop and Call a Plumber If…
- Cleaning the aerator doesn't restore pressure — the cartridge may be failing
- The fixture is old and parts may be discontinued
- Water is also leaking from the fixture (not just low pressure)
- Both hot and cold are low at the same fixture (unlikely to be aerator alone)
- ✓Removing and inspecting the cartridge for blockage or wear
- ✓Checking the supply line for kinks or blockage
- ✓Testing the supply valve for proper operation
- ✓Replacing the cartridge with the correct part for the faucet brand
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Reviewed by Paul Hall, Owner & Licensed Plumber
The Classic Plumber · Knoxville, TN · License #4268. This guidance is general — an onsite inspection may be required for a confirmed diagnosis.