What a sink aerator is and why you'd replace one

A sink aerator is the small screened piece screwed onto the end of your faucet spout. Water passes through it before it comes out, mixing air into the stream so it flows smoothly without splashing. Over time, mineral deposits clog the screens, water pressure drops, or the aerator cracks and leaks. Replacing it is faster and cheaper than calling a plumber — the part costs $3 to $15, and the job takes about ten minutes with no special tools.

You'll know you need a replacement when water comes out in a weak spray instead of a solid stream, or when you see water pooling around the base of the spout instead of flowing through the aerator. Sometimes the aerator straightforward unscrews and cleans, but if cleaning doesn't restore pressure or if it's visibly damaged, replacement is the better choice.

Key Takeaways

  • Most aerators unscrew by hand or with a wrench; turn counterclockwise to loosen, and you do not need to turn off the water.
  • Before you buy a replacement, measure the diameter of the threaded opening on your spout or bring the old aerator to the hardware store to match it.
  • Aerators come in standard sizes — 15/16 inch and 55/64 inch are the most common — and cost between $3 and $15 depending on flow rate and finish.
  • Wrap the spout threads with plumber's tape before screwing on the new aerator to prevent leaks and make future removal easier.
  • Hand-tighten the new aerator; do not use a wrench, because overtightening can crack the plastic or strip the threads.

Gather your tools and measure the old aerator

You need almost nothing: a wrench (adjustable or 10-inch crescent), plumber's tape (also called PTFE tape or Teflon tape), and the replacement aerator itself. The wrench is optional — most aerators unscrew by hand — but it helps if the old one is stuck tight. Do not turn off the water; you do not need to.

Before you go to the store, unscrew the old aerator by hand. Grip the spout with one hand and turn the aerator counterclockwise with the other. If it won't budge, wrap a cloth around it to improve your grip, or use the wrench. Once it's off, look at the threaded opening on the spout. The diameter is printed on the aerator itself, or you can measure it with a ruler — most are either 15/16 inch or 55/64 inch. Bring the old aerator with you to the hardware store, or write down the size and flow rate (usually 1.5 or 2.2 gallons per minute).

Buy the right replacement aerator

Aerators are sold in the plumbing section of any hardware store, usually near the faucet repair kits. They come in two standard sizes: 15/16 inch (the most common) and 55/64 inch. The difference is small but matters — if you buy the wrong size, it won't thread onto your spout. The easiest way to be sure is to bring the old aerator with you and match it, or ask a store employee to help you thread it onto the spout before you leave.

You'll see aerators labeled by flow rate — 1.5 gallons per minute (GPM) is standard and saves water, while 2.2 GPM flows faster. If you're replacing an old aerator, match the flow rate unless you want to change water pressure. The finish (chrome, brushed nickel, stainless steel) should match your faucet, though this is cosmetic and doesn't affect function. Most replacement aerators cost between $3 and $8.

Remove the old aerator and clean the spout threads

Turn the old aerator counterclockwise by hand. If it's stuck, wrap a cloth around it to grip it better, or use an adjustable wrench — grip the spout with one hand so you don't twist the faucet itself. Once it's off, look inside the spout opening. You'll see male threads (ridges) where the aerator screwed on. Use a dry cloth or old toothbrush to wipe away any mineral buildup, debris, or old tape. This takes 30 seconds and makes the new aerator seal better.

If you see white or tan crusty buildup, soak a cloth in white vinegar and hold it against the threads for a minute, then brush again. Do not use a wire brush or anything abrasive — you can damage the threads. Once the threads are clean and dry, you're ready to install the new aerator.

Wrap the threads with plumber's tape

Plumber's tape (PTFE or Teflon tape) is a thin white tape that wraps around male threads to seal them and prevent leaks. It costs about $2 and lasts for dozens of projects. Tear off a piece about 12 inches long. Hold the spout in one hand and wrap the tape clockwise around the threads three times, stretching it slightly as you go. The tape should cover all the threads but not bunch up. Smooth it down with your finger so it lies flat.

This step is optional if you're in a hurry, but it prevents leaks and makes the aerator much easier to remove next time. If you skip it and the aerator leaks, you can always unscrew it, add tape, and screw it back on.

Screw on the new aerator and test the water

Hold the spout steady with one hand. With the other hand, thread the new aerator onto the spout by turning it clockwise. Start by hand — the threads should catch smoothly. If you feel grinding or resistance, stop and check that you're turning clockwise and that the aerator is lined up straight. Once the aerator is hand-tight, turn it one more quarter-turn to seat it firmly. Do not use a wrench — hand-tight is correct. Overtightening can crack plastic aerators or strip the threads.

Turn on the water and check for leaks around the base of the aerator. The water should flow in a smooth, even stream without splashing. If you see water dripping from where the aerator meets the spout, turn off the water, unscrew the aerator, add another wrap of plumber's tape, and screw it back on. If the water pressure is still weak after replacement, the problem may be inside the faucet itself, not the aerator.

Common mistakes to avoid

The most common error is buying the wrong size. If you're not sure whether your aerator is 15/16 inch or 55/64 inch, bring the old one to the store or call ahead and describe your faucet. Trying to force the wrong size onto the spout can strip the threads and create a much bigger problem.

The second mistake is overtightening. Many people use a wrench to tighten the new aerator "to be sure," which cracks plastic aerators or damages the threads on the spout. Hand-tight is the correct tightness — if it leaks, the fix is plumber's tape, not more force. A third mistake is forgetting to clean the spout threads before installing the new aerator; mineral buildup prevents a good seal and causes leaks.

Frequently Asked Questions

Do I have to turn off the water to replace an aerator?

No. Water may dribble out when you unscrew the old aerator, but it stops as soon as you screw the new one on. Have a cloth handy to catch drips, but you do not need to shut off the main water valve.

What if the aerator won't unscrew by hand?

Wrap a cloth around it for a better grip and try again. If that doesn't work, use an adjustable wrench to turn it counterclockwise, but hold the spout steady with your other hand so you don't twist the faucet. Soak the joint with white vinegar for a few minutes if it's stuck from mineral buildup.

Can I clean the old aerator instead of replacing it?

Yes, if it's not cracked or leaking. Unscrew it, soak it in white vinegar for 30 minutes, then brush the screens with an old toothbrush and rinse. Screw it back on and test. If water pressure doesn't improve or if you see cracks, replacement is the better choice.

What's the difference between 1.5 and 2.2 GPM aerators?

GPM (gallons per minute) is the flow rate. 1.5 GPM is standard and uses less water; 2.2 GPM flows faster. If your old aerator was 1.5 GPM and you want to save water, buy 1.5 GPM. If you want more pressure, buy 2.2 GPM. The size (15/16 or 55/64 inch) is what matters for fitting your spout.

Why is water leaking where the aerator meets the spout?

The threads aren't sealed. Unscrew the aerator, wrap the spout threads with two or three layers of plumber's tape, and screw it back on. If it still leaks after that, the spout threads may be damaged and you may need a new faucet.