Start with the aerator and shut-off valve

The fastest fix for low kitchen sink pressure is cleaning or replacing the aerator — the small screen at the tip of your faucet. Mineral buildup and debris collect there and restrict flow. Unscrew it by hand (turn counterclockwise), rinse it under hot water, and use an old toothbrush to scrub the mesh. If it is badly clogged, soak it in white vinegar for an hour first.

While you have the aerator off, check the shut-off valve under the sink. It is a small knob on the water line coming in. Turn it fully counterclockwise — sometimes it gets partially closed by accident and nobody notices. If the valve is stuck or will not turn smoothly, it may be corroded and need replacement, which a plumber can do in under an hour.

These two steps solve the problem in roughly 70 percent of single-sink pressure complaints. If pressure returns to normal, you are done. If not, move to the next section.

Key Takeaways

  • Clean the aerator (the screen at your faucet tip) first — mineral buildup is the most common cause of low pressure at one sink.
  • Check that the shut-off valve under your sink is fully open; a partially closed valve cuts pressure without any other sign of trouble.
  • If only your kitchen sink is slow but other faucets run normally, the problem is almost always in the sink line itself, not your whole house.
  • A clogged supply line may need to be flushed or replaced by a plumber, which typically costs between $150 and $300.
  • If all faucets in your house are slow, the issue is likely at the meter or main shut-off, and you should contact your water company or a plumber.

Flush the supply line if pressure is still low

If cleaning the aerator and opening the shut-off valve did not work, sediment or debris may be stuck inside the supply line itself. Turn off the shut-off valve completely, then unscrew the supply line (the flexible hose connected to the valve). Hold it over a bucket and turn the valve back on briefly to flush out whatever is inside. You may see rust, sand, or mineral flakes come out.

Screw the line back on and test the pressure. If it improved but is still weak, the blockage may be deeper in the line. At that point, a plumber can disconnect the line at both ends and run water through it at high pressure, or replace it entirely if it is old or corroded.

Inspect the faucet body for internal clogs

Some faucets have a small screen or cartridge inside the body that can clog. If your faucet is older than 10 years and pressure has been dropping gradually, this is worth checking. Look up your faucet model online — most manufacturers publish diagrams showing how to remove the cartridge or internal parts.

The cartridge usually unscrews or slides out. Rinse it thoroughly under hot water and soak it in vinegar if there is visible mineral buildup. Reinstall it and test. If you are not comfortable taking the faucet apart, a plumber can do this in 30 to 45 minutes.

Check whether the problem is only at your sink

Before calling a plumber, turn on every other faucet in your house — bathroom sinks, shower, outdoor hose, washing machine. If they all run at normal pressure, the problem is isolated to your kitchen sink line and you can follow the steps above. If they are all slow, the issue is upstream: at your water meter, main shut-off valve, or the water company's side of the line.

In that case, contact your water company first. They can check the meter and main line for free. If they find no problem, a plumber will need to inspect your main shut-off valve and the line from the meter into your house, which usually costs $100 to $200 for a service call.

Know when to replace the faucet

If the aerator is clean, the shut-off valve is open, the supply line is clear, and pressure is still low only at that sink, the faucet itself may be failing internally. Faucets typically last 15 to 20 years. If yours is older and pressure has been declining, replacement is often cheaper than repeated repairs.

A new kitchen faucet costs between $40 and $200 depending on style and features. Installation by a plumber usually runs $100 to $150. If your current faucet is under warranty (usually five years), contact the manufacturer — they may replace it at no cost.

Understand why pressure drops at one sink

Water pressure at a single faucet depends on three things: the supply line from the meter to your house, the shut-off valve under that sink, and the faucet itself. If the other faucets in your house run fine, you know the main line is not the problem. That narrows it down to the valve, the supply line between the valve and faucet, or the faucet body.

Mineral deposits from hard water are the most common culprit. They build up in the aerator first, then in the supply line, and eventually inside the faucet cartridge. Vinegar soaks and flushing remove most deposits. If your water is very hard, installing a water softener on your main line can slow future buildup, though that is a separate project and costs $500 to $2,000 installed.

Frequently Asked Questions

Can low pressure at my kitchen sink mean a leak?

Not usually. A leak would show up as water dripping under the sink or pooling in the cabinet. Low pressure without visible water means a clog or partially closed valve. Check under the sink with a flashlight and feel the supply line and connections. If everything is dry, the problem is almost certainly a blockage.

Should I use a chemical drain cleaner to unclog the supply line?

No. Drain cleaners are designed for drain pipes, not supply lines, and can damage faucet seals and cartridges. Stick to vinegar soaks and flushing with water. If the line is severely clogged, a plumber can use a water jet or replace the line.

Why is my kitchen sink pressure low but the bathroom sink is fine?

The kitchen and bathroom have separate supply lines from the main shut-off valve. A clog or closed valve in the kitchen line will not affect the bathroom. Follow the steps in this guide starting with the kitchen aerator and shut-off valve.

How do I know if my shut-off valve is broken?

A broken valve will not turn smoothly, may feel stuck, or may leak when you try to close it. If it is stuck, do not force it — you could break it further. Call a plumber to replace it. A new shut-off valve costs $30 to $80 plus labor.

Will a water softener fix low pressure?

A water softener prevents future mineral buildup but will not clear existing clogs. Clean the aerator and flush the line first. A softener is worth considering only if you have hard water and pressure problems keep returning.