Quick Answer:
A sharp whistling or squealing right after fitting a new aerator usually comes from a small restriction or a misaligned part in the aerator or faucet. First remove the aerator and retest the flow, inspect the screen for debris or warping, then reinstall it loosely to compare the tone. If the sound continues after those checks, a plumber can safely find and fix the exact restriction.
Why This Happens
An aerator adds tiny holes and mixing chambers at the faucet tip. If one of those holes is partially blocked, the screen is warped, or the aerator doesn’t seat straight, fast-moving water can create a high-pitched whistle. Similar effects happen when valves or internal fittings create a narrow path for flow, and the noise can change with pressure or handle position. This issue can be similar to Whistling when two fixtures run, and if opening a valve changes the sound you may want to compare this to Noise stops when valve opened fully.
Step-by-Step What to Do
1. Remove the aerator and retest flow
- Use your fingers or a soft cloth around the aerator to unscrew it. If needed, use adjustable pliers with a cloth to protect the finish.
- Run the tap briefly without the aerator to see if the whistling goes away. If the noise disappears, the aerator is the likely cause.
- Keep small parts (washers, screens) safe so you don’t lose them.
2. Inspect for debris or a warped screen
- Look for grit, mineral buildup, or a distorted screen. Hold the parts up to light to spot warped edges.
- Clean with a soft brush and, if needed, soak in a mild vinegar solution to remove mineral deposits. Rinse thoroughly before testing.
- If the screen is bent or the plastic is deformed, it may not seat correctly and should be replaced.
3. Reinstall loosely and compare tone
- Screw the aerator back in by hand, snug but not over-tight. Test the water flow and listen for changes in pitch.
- Try tightening a small amount to see if the tone shifts; if tightening increases vibration or produces a new noise, stop and leave it slightly loose for comparison.
- If removing the aerator eliminates the noise entirely, try a different or replacement aerator to confirm.
What Not to Do
- Don’t drill out aerators or force threads.
- Warped parts are easier replaced by a plumber.
- Avoid hammering or using excessive force on faucet parts; that can damage finishes and internal components.
When to Call a Professional
Call a plumber if the whistling persists after removing, cleaning, and loosely reinstalling the aerator, or if you suspect the noise comes from a valve, cartridge, or hidden pipe restriction. If the sound changes with handle position or a shutoff valve, a pro can diagnose internal restrictions or worn parts without causing damage. Also call for help if you can’t access the parts, if fittings are seized, or if you’re uncomfortable using tools on the faucet.
Safety Notes
- Turn the water off at the fixture or house shutoff if you’re going to disassemble deeper parts or work on valves.
- Protect the faucet finish with a cloth when using pliers to avoid slipping and scratching.
- Do not use power tools or aggressive chemicals on small faucet parts. If you encounter stuck or corroded pieces, stop and call a professional.
Common Homeowner Questions
- Will a new aerator always whistle? No. Most new aerators are quiet; whistling usually means a fitment or damage issue.
- Can I fix a warped screen myself? You can replace a small, damaged aerator cheaply yourself, but avoid trying to reshape it—replacement is better.
- Is whistling a sign of imminent failure? Not usually, but persistent noise can point to a worn valve or internal restriction that a plumber should check.
For more related articles, see the Whistling or Screeching Noises in Pipes hub.