Quick Answer:
If you hear a sharp whistling or squealing from a faucet when you open it, the sound usually comes from water flowing through a narrowing or a worn part that vibrates. Start by testing how the pitch changes with flow, check the aerator and cartridge screens, and compare with nearby fixtures. If the noise continues after those basic checks, a plumber can safely locate the exact restriction and make a lasting repair.
Why This Happens
Whistling or squealing is caused by fast-moving water forcing its way past a partial restriction or a loose part. Common culprits:
- Debris or mineral buildup in the aerator or cartridge screens.
- A worn valve seat, cartridge, or washer that allows thin streams to form and vibrate.
- Partially closed supply valves or partially blocked pipes creating high velocity.
- High house water pressure or sudden pressure changes in the supply lines.
- Loose internal parts that resonate when water flows.
One quick clue: if the pitch changes with flow, that points to a flow-related obstruction rather than electrical noise or external vibration. Comparing fixtures can tell you if the issue is local to one faucet or affects the whole house. For related noises elsewhere, see Toilet squeals while refilling and Whistling after installing aerator.
Step-by-Step What to Do
Run the faucet at low, medium, and full flow
- Open the faucet slightly, then to medium, then fully. Note how the pitch and volume change at each setting.
- If the pitch rises or becomes more shrill at certain flows, that indicates a restriction or vibrating part that only engages at that velocity.
- Make brief notes so you can describe the behavior to a plumber if needed.
Compare with a nearby faucet
- Turn on another faucet on the same supply line (same floor or bathroom) to see if it whistles as well.
- If only one faucet sings, the problem is almost certainly localized to that fixture’s valve, cartridge, or aerator.
- If multiple faucets whistle, consider checking supply valves or water pressure for the whole house.
Inspect the aerator and cartridge screens
- Unscrew the aerator and inspect it for debris or mineral buildup; rinse or soak it in vinegar if clogged.
- If the faucet allows, remove the handle (with the water off) and look at the cartridge screens or inlet screens for grit.
- Clean screens and reassemble carefully; if the screens are damaged or removal is unclear, stop and call a plumber.
Check supply valves and visible fittings
- Make sure the shutoff valves under the sink are fully open.
- Look for loose nuts or clamps and gently tighten if you can do so with basic tools—don’t force them.
When replacement is necessary
- If cleaning doesn’t stop the noise, the cartridge, valve seat, or washer may be worn and need replacement.
- Replacement is a common fix but requires the right part and sometimes brand-specific knowledge.
What Not to Do
- Don’t overtighten faucet parts to silence the noise—forcing components can crack fittings, strip threads, or damage seals.
- Don’t keep running the faucet at high flow to “test” it for long periods; that wastes water and can mask intermittent behavior.
- If cartridge access is unclear, let a plumber service it rather than prying parts that may be hidden or corroded.
- Don’t use aggressive chemical descale products on internal cartridge parts unless the product is explicitly recommended by the manufacturer.
When to Call a Professional
Call a plumber when:
- The whistling continues after you’ve run the faucet at different flows and cleaned screens.
- You can’t access or identify the cartridge or internal parts without risking damage.
- There are accompanying problems like leaks, sudden loss of pressure, or the noise occurs across multiple fixtures.
A licensed plumber can pinpoint an internal restriction, test water pressure, and replace worn cartridges or seats safely.
Safety Notes
- Always shut off the water supply at the shutoff valves before removing a handle or cartridge.
- Relieve any pressure by opening the faucet after the shutoff is off, then work with cloths or a small bucket to catch water.
- Use the right-size tools to avoid stripping screws or handles. If something is stuck, stop rather than force it.
- When in doubt about electrical proximity, hot-water scald risk, or complex valve work, hire a professional.
Common Homeowner Questions
- Is a whistling faucet dangerous? No—usually it’s annoying rather than dangerous, but it can indicate a failing part that should be fixed.
- Will replacing the aerator fix it? Sometimes; if the aerator or its screen is clogged, cleaning or replacing it can stop the noise.
- Can I keep using the faucet until the plumber arrives? Yes, but avoid high flow for long periods and stop if you hear grinding or see leaks.
For more related articles, see the Whistling or Screeching Noises in Pipes hub.