Faucet Low Pressure: Causes and Fixes
Weak flow at a single faucet is one of the most local problems in plumbing — and one of the easiest to misdiagnose as a whole-house issue. When every other t…
This page explains a common plumbing problem. It is general information, not a diagnosis of any specific home.
Weak flow at a single faucet is one of the most local problems in plumbing — and one of the easiest to misdiagnose as a whole-house issue. When every other tap runs fine, the cause is almost always in or just beneath that one faucet.
The usual suspects, in order of likelihood, are the aerator, the cartridge, and the supply valves beneath the sink. Checking them in that order solves most single-tap pressure complaints without touching anything else.
Common Causes
- A clogged aerator full of sediment and mineral scale
- A cartridge partially blocked by debris
- A supply valve beneath the sink that is not fully open
- A kinked or restricted supply line
- A diverter or sprayer fault in a kitchen faucet
Safe Checks You Can Do First
- Unscrew and clean the aerator first — it solves most single-tap complaints
- Check that both supply valves beneath the sink are fully open
- Compare hot and cold flow: one side weak points to that side's cartridge or valve
- Note whether the problem appeared suddenly (a dislodged particle) or gradually (scale buildup)
- If every tap is weak, the cause is not the faucet — it is further back in the system
When Professional Help Fits
If the checks do not resolve the problem, if water is spreading, if sewage is involved, or if gas is suspected, professional help fits now rather than later. For a suspected gas leak, leave the area and call emergency services or the gas utility from a safe location.
Frequently Asked Questions
Why is only my kitchen faucet weak?
Usually its aerator or cartridge. Kitchen faucets also have sprayers and diverters that can restrict flow. The rest of the house running fine is the clue that the problem is local.
Does cleaning the aerator really help?
Yes, often dramatically. Aerators catch sediment and scale, and a clogged one can cut flow by more than half. It unscrews by hand on most faucets and rinses clean.
When is low pressure at one tap a bigger problem?
When cleaning the aerator and checking the valves does not help, or when the weakness spreads to other taps. At that point the cause may be a supply restriction or a wider pressure issue.
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