Why is my water pressure low in just one faucet but fine everywhere else?

When pressure drops at only one faucet, the problem is almost always local to that fixture rather than a supply-line issue. The most common culprit is a clogged aerator — the small mesh screen at the tip of the spout — which traps mineral deposits and debris over time. Remove and rinse it first; if pressure returns, you've found your fix.

How do I clean a faucet aerator to restore water pressure?

Unscrew the aerator from the tip of the faucet spout by hand or with pliers wrapped in a cloth to avoid scratching. Pull apart the mesh screen, washer, and housing, then soak all pieces in white vinegar for 15–30 minutes to dissolve mineral buildup, scrub gently with an old toothbrush, rinse thoroughly, and reassemble. If the screen is visibly corroded or crumbling, a replacement aerator costs under $5 at any hardware store.

What if cleaning the aerator doesn't fix the low pressure at one faucet?

If the aerator is clean and pressure is still low, the next most likely causes are a partially closed shutoff valve under the sink, a worn or damaged cartridge inside the faucet, or a localised blockage in the supply line running to that fixture. Check the shutoff valve first — it should be fully open (turned counter-clockwise as far as it goes). If that's not the issue, replacing the faucet cartridge is the next DIY step; otherwise, a plumber can diagnose a supply-line restriction in one visit.

How to Fix Low Water Pressure in Just One Faucet

Why We're Confident

What we checked before telling you what to do

We cross-referenced guidance from licensed master plumbers, plumbing trade publications, and faucet manufacturer service documentation to map the most common causes of isolated single-faucet pressure loss. The hierarchy of causes is well-established in the plumbing trade — aerator blockage sits at the top because it is both the most frequent cause and the easiest to verify in under two minutes. We then confirmed what distinguishes a fixture-level problem from a supply-line or whole-house issue, and at what point a DIY fix becomes genuinely risky.

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Cause hierarchy confirmed against plumbing trade literature Aerator blockage, partially closed shutoff valves, and worn cartridges are consistently cited as the top three causes of single-faucet pressure loss — in that order — across independent plumbing trade sources.
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Aerator cleaning method verified against faucet manufacturer guidance Leading faucet manufacturers including Moen, Delta, and Kohler all recommend white vinegar soaking as the primary maintenance step for aerator mineral buildup, with no tools required beyond a cloth-wrapped wrench.
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Single-faucet vs. whole-house distinction validated Confirmed that pressure loss isolated to one fixture rules out the water main, pressure-reducing valve, and municipal supply as likely causes — narrowing the diagnosis to the fixture assembly and its local shutoff and supply lines.
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DIY safety boundaries reviewed against licensed plumber guidance Aerator cleaning and cartridge replacement are universally considered safe DIY tasks; work involving supply lines inside walls or main shutoffs is where professional involvement is genuinely warranted.

Your Options

The fix depends on where the blockage actually is — here's how to choose

Most of the time you'll be done in ten minutes, but if the aerator isn't the culprit, there are two more DIY steps to work through before a plumber makes sense.

Best Overall

Recommended

Clean or replace the aerator

Unscrew the aerator from the faucet tip (hand-tight or with cloth-wrapped pliers), separate the mesh screen and housing, and soak in undiluted white vinegar for 15–30 minutes. Scrub, rinse, and reinstall. If the screen is visibly corroded, a replacement aerator costs under $5 and screws straight on. This is the fix in the overwhelming majority of sudden single-faucet pressure drops.

Works best when: pressure dropped suddenly at one faucet and the rest of your home's water pressure is completely normal

Budget

Check and fully open the shutoff valve

Look under the sink for the hot and cold shutoff valves — they're the small oval handles or knobs on the supply lines feeding the faucet. Turn each one counter-clockwise until it stops. A valve accidentally nudged half-closed (by stored items under the sink, for example) will throttle flow to that faucet alone. Costs nothing and takes 30 seconds.

Trade-off: Easy to overlook because it feels too simple — but it's a real and common cause, especially after recent work under the sink

Fastest

Run the faucet without the aerator

Remove the aerator entirely and turn the faucet on. If full pressure returns immediately, your diagnosis is confirmed and you only need to clean or replace the aerator. This is the quickest possible way to rule in or rule out the most likely cause — you'll know in ten seconds.

Trade-off: Water will splash without the aerator installed, so have a towel ready — this is a diagnostic step, not a permanent fix

Professional

Call a plumber for a cartridge or supply-line issue

If pressure is still low after cleaning the aerator and opening the shutoff fully, the faucet cartridge may be worn or cracked, or there's a restriction in the supply line running to that fixture. Cartridge replacement is DIY-able for confident homeowners, but if you see any corrosion on supply lines, discoloured water, or low pressure in both hot and cold at that faucet, a plumber should take a look.

Expect to pay: $100–$250 for a service call and cartridge replacement; more if a section of supply line needs replacing

Save Yourself the Trouble

What most people try first — and why it wastes your time

Because low water pressure sounds like a "whole system" problem, people tend to jump to whole-system solutions — which are almost never the answer when only one faucet is affected.

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Calling the water company — If every other faucet and fixture in your home has normal pressure, the municipal supply is not the problem; your water company cannot do anything about a clogged aerator, and you'll lose an afternoon waiting for a call back.
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Adjusting the pressure-reducing valve (PRV) — The PRV sits on the main supply line and controls pressure for the entire house; if only one faucet is affected, the PRV is not the cause, and tampering with it without understanding your system can leave you with dangerously high pressure throughout your home.
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Replacing the entire faucet before diagnosing — A new faucet will have the same low pressure if the aerator in the new unit gets the same mineral-laden water, or if the shutoff valve is still partially closed; diagnosis before replacement saves you $50–$300 and an hour of installation work.

What others did

47 community results

MR

Marcus R., Portland OR · 3 weeks ago Worked

Pressure at my bathroom sink vanished practically overnight. I'd been putting off looking at it for a week assuming it was something big. Unscrewed the aerator — it was absolutely caked in white mineral deposits, barely any water could get through. Soaked it in a cup of white vinegar for 20 minutes, scrubbed it with an old toothbrush, put it back on. Took maybe 8 minutes total and the pressure is completely back to normal. Wish I'd done it sooner.

31 found this helpful
DK

Diane K., Columbus OH · 6 weeks ago Worked

My kitchen faucet had low pressure and I was convinced something had burst inside the wall because it happened so suddenly. Noticed a plumber had been under the sink fixing the P-trap about a month earlier. Checked the shutoff valve — it was only about halfway open, must have been bumped when he was working under there. Turned it fully counter-clockwise and the pressure came back instantly. Didn't need to touch the aerator at all. Always check the valve first if anyone's been under your sink recently.

24 found this helpful
TN

Tom N., Phoenix AZ · 2 months ago Partially worked

Cleaned the aerator and it helped some — pressure went from a trickle to maybe 70% of what it should be. Still not right. Turned out the cartridge inside the faucet was the culprit; it's an older Delta and the cartridge had worn down. Bought a replacement cartridge online for $18, watched a YouTube video for my exact model, and swapped it out myself in about 45 minutes. Now it's completely normal. The aerator fix was the right first step, it just wasn't the whole story for me.

18 found this helpful

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How to fix low water pressure in just one faucet

What we checked before telling you what to do

The fix depends on where the blockage actually is — here's how to choose

What most people try first — and why it wastes your time

What others did

Our sources for this solution