Low water pressure at the faucets: one fixture or the whole house?

A weak stream at the kitchen faucet feels like a house problem, but it is often a small one at the tip of the spout. Faucet makers point out that the screened fitting there, the aerator, can get dirty or calcified over time, and that is a common reason a stream sputters or thins out. Before you worry about pipes, work out how wide the problem is.

One faucet is usually something you can handle in a few minutes with a rag and a small brush. Every faucet, the shower and the washing machine all running weak points somewhere else, and those causes belong to your water provider or a licensed plumber.

This guide does the sorting first. It then walks through cleaning an aerator, says how to use a pressure gauge reading if you choose to take one, and ends with a table that shows which result means DIY and which means a pro. Nothing here asks you to open a wall, touch a main shutoff or work on anything that needs a license.

What's going on

Start with the test. Run the cold water at the faucet that bothers you, then the hot. Walk to another sink, then a tub and a shower, and compare how each one flows. It helps to write down what you see, because the pattern is most of the answer.

• Weak at one faucet only: suspect that faucet's aerator, the small screened fitting on the end of the spout.
• Weak at one faucet, but only hot or only cold: the problem is still local to that fixture or its supply line, so start with the aerator and see whether anything changes.
• Weak at every fixture: the cause is upstream of the faucets, either on the street side or somewhere in your private plumbing. Ask a neighbor whether their water is weak too, and ask your water provider about local work.

Why a tiny screen matters: a faucet maker's own care page says aerators may become dirty or calcified over time, especially where tap water carries many suspended solids or lime. You can read it on the faucet maker's aerator care page. The same page notes that a clogged aerator can spoil hand washing, which is the symptom most people notice first.

If you live where the water is hard, or where the water carries a lot of particles, an aerator problem is more likely. That is a reason to check the aerator before anything else.

What you can safely check or fix

Cleaning an aerator needs no license and no shutoff of the house supply. Do the faucet that is weak first. Fittings differ from model to model, so your faucet maker's own instructions for your faucet come first, and where they differ from the list below, follow them.

1. Find your faucet maker's instructions for your model.
2. Put a rag over the sink drain so a dropped piece cannot fall in.
3. Look at the spout tip to see whether the aerator sits on the outside or inside.
4. Unscrew the aerator the way your maker's instructions describe.
5. Lay the pieces out on the rag in the order they came off.
6. Rinse loose debris from the screen under running water.
7. Look the screen over for mineral buildup or damage.
8. Put the pieces back together in the order you laid them out.
9. Screw the aerator back on by hand until it is snug.
10. Run the water and compare it with the other faucets.
11. Repeat the same steps at the next faucet.

If mineral buildup will not rinse off, use only the cleaner your faucet maker's instructions name, and rinse well afterward.

If a part is worn or cracked, a replacement aerator is a simple swap. The EPA says a WaterSense aerator can be installed by twisting it on. The EPA also says WaterSense sets a minimum flow rate so labeled products give adequate flow at low water pressure. That is the EPA describing its label, not a recommendation of any one item. See the EPA's WaterSense faucet page for details.

Where to stop and call a pro

If the aerator is clean and the stream is still weak, or if the whole house is affected, the remaining causes are not DIY repairs. A dirty or calcified aerator is the local cause the maker's page describes, so once that is ruled out, the problem is somewhere else.

Stop here: If every fixture is weak and your neighbors are fine, or you suspect a leak or a faulty valve on your supply line, stop and call a licensed plumber.

Before you book anyone, ask your water provider about local work or a main break. A street-side cause is not something a plumber can fix inside your house, and a quick call can save a visit. If the provider says the problem is not on its side, the cause is in your private plumbing, and that is plumber territory.

Do not open or adjust the pipes where your supply enters the house, and do not cut into walls or floors to chase a leak. Those jobs belong to a licensed plumber. To confirm a plumber's license, use your state licensing board's lookup. Fix-It Review's directory links each listed license to the state's own lookup.

What to tell the pro

A few plain facts save time on the phone:

• Whether the low pressure is at one faucet or every fixture.
• Whether you cleaned the aerator, and whether the screen was dirty or calcified.
• Whether hot, cold or both are weak.
• When it started, and whether street work or a main break happened nearby around then.
• Whether neighbors have the same problem, and what your water provider said.
• Any noisy pipes, or any damp spots you have noticed.
• Any gauge reading you took, with the place you took it.

Optional: a pressure gauge reading

If you want a number, a pressure gauge on an outdoor hose bib will give one. Follow the instructions that come with the gauge. Then compare the reading with your water provider's normal range for your address. Write the number down, with the place and time, and give it to the plumber. A low reading fits with weak flow at every faucet. It does not replace the aerator check, since a clogged aerator can spoil flow at a single faucet whatever the supply pressure is.

Which result means DIY, which means a pro

| What you find | Likely cause | Next step |
|---|---|---|
| One faucet weak, others fine | Clogged or calcified aerator | DIY: clean it with the steps above |
| Weak right after street work | Debris or work on the supply | DIY: clean aerators, and ask your water provider about the work |
| Neighbors also weak | Provider-side issue | Call your water provider |
| Every fixture weak, neighbors fine | Private plumbing | Pro: licensed plumber |
| Every fixture weak and noisy pipes | Possible valve or leak problem | Pro: licensed plumber |

Need one? Use Find a Pro on this site to search your state and trade.

Quick answers

How do I tell if low pressure is just one faucet?

Compare other sinks, the tub and the shower. If only one faucet is weak, a dirty or calcified aerator is a likely cause, according to a faucet maker's care page.

Can I fix a clogged aerator myself?

Yes, cleaning an aerator needs no license. If a part is worn, the EPA says a WaterSense aerator can be installed by twisting it on.

When is low pressure a job for a plumber?

When the aerator is clean and every fixture is still weak, the cause is beyond the faucet. Ask your water provider about local work first, then call a licensed plumber.