Symptoms
- Weak flow from one specific faucet
- Other faucets and the shower are normal
- Both hot and cold are weak at that faucet
- Flow improved briefly after cleaning, then dropped again
Likely causes
- CommonClogged aerator screenSediment and mineral scale collect in the small mesh screen at the spout tip.
- CommonPartly closed shutoff valveValves under the sink are sometimes not fully reopened after work.
- PossibleKinked or clogged supply lineFlexible lines can kink behind the cabinet or clog with debris.
- PossibleClogged cartridge or valve internalsSediment can lodge inside the faucet body itself.
What to do
- Check that both shutoff valves under that sink are turned fully open (counterclockwise).
- Unscrew the aerator from the tip of the spout by hand or with pliers wrapped in a cloth.
- Rinse the aerator screen and soak it in vinegar for 15–30 minutes to dissolve mineral buildup.
- Run the faucet without the aerator attached to see if pressure improves; if so, the aerator was the cause.
- Reinstall the cleaned aerator and test again.
- If flow is still weak, check the supply lines under the sink for kinks or damage.
- If pressure is still low with clean lines and a clean aerator, the cartridge may need cleaning or replacing.
Tools and parts
- Pliers
- Small brush
- Vinegar
Replacement aeratorSearch: “faucet aerator replacement standard size”
When to call a pro
Call a plumber if pressure stays low after cleaning the aerator and checking valves, since the cartridge or internal plumbing may need attention.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.