Why Does My Toilet Whistle When I Flush?

“Whistle While You Work” is a familiar tune, but your toilet shouldn’t be tooting away while it’s doing its job. Toilets make an orchestra of sounds when they flush, drain and refill, but whistling is out of the ordinary. If you hear a high-pitched whistle coming from your bathroom, it’s time to do some investigating.

If you hear whistling coming from your toilet, it can be more than just a nuisance. In the bigger picture, it means your toilet isn’t running as efficiently as it should be. It could be a minor problem, like the water supply valve isn’t fully open, or you could be wasting water because of a faulty fill valve. If you’re a homeowner with a little bit of DIY knowledge, repairing a whistling toilet can be an easy job, if you know where to look.

  1. Check the water supply valve.

    Oftentimes, a toilet starts whistling when something restricts the water flow to the toilet. First, check the toilet’s water supply valve. This knob is usually located behind the toilet near the wall. Since it is located close to the ground and easy to turn, it’s easy for children to unknowingly prank their parents by closing the valve. Turn the valve counterclockwise to make sure it’s completely open. If you still hear whistling, you’ll need to remove the cover to the toilet’s tank, and conduct a deeper investigation.
  2. Inspect the fill valve.

    Most likely, if the whistling isn’t coming from the water supply valve, it’s coming from the fill valve. Usually, this is the case for old toilets that operate using a metal ballcock valve. The fill valve is often located in the rear left corner of the toilet. Try flushing the toilet to see if you can hear where the whistle is coming from.

    If it sounds like the whistle is coming from the fill valve, do a visual inspection to see if there is any debris restricting the water flow. Over time, mineral deposits can collect around the fill valve, which restricts water from flowing through the valve. Use a damp rag to wipe off any deposits that have collected on the valve.
  3. Replace the fill valve.

    After you’ve cleaned off the fill valve, flush the toilet one more time. If the toilet is still whistling, it’s time to replace the fill valve. If you have an old metal ballcock valve toilet, it’s possible to replace the gasket and stop the whistling. However, newer replacement fill valves are constructed from plastic and relatively inexpensive. A plastic fill valve is less likely to create whistling sounds in the future compared to a metal one. When metal vibrates, it can resonate, which creates additional ringing and whistling sounds from the toilet. In addition, newer fill valves are more efficient than their old counterparts, which allows you to conserve water and save on your water bill.

    While it may seem intimidating, replacing a toilet fill valve is simple and only requires a few tools. After you’ve purchased your new fill valve, do the following:

    1) Turn off the water supply valve to the toilet.
    2) Flush the toilet.
    3) Soak up any remaining water in the tank with a sponge or old towel.
    4) Using a wrench, disconnect the old supply line from the toilet tank.
    5) Disconnect the fill tube connected to the overflow pipe.
    6) Unscrew the valve nut keeping the fill valve in place.
    7) Remove the fill valve.
    8) Position the new valve in the tank, making sure the washers are in the correct place.
    9) Using your hands, tighten the lock nut onto the threaded part of the fill valve underneath the tank.
    10) Reattach the water supply line to the bottom of the fill valve using a wrench.
    11) Turn on the water supply and check for any leaks.
    12) Following the instructions that came with your fill valve, adjust the float so that it sits about one inch below the overflow pipe. You can adjust some floats using a clip on the side, others will require a screwdriver.
    13) Once the tank is full, and the water stopped running, flush the toilet to make sure it’s working properly and there aren’t any leaks.

If your toilet is still whistling, or if you need help installing a new fill valve, call Kenny Bunch Plumbing at: 972-429-5213.

Our knowledgeable experts can help get your annoying, whistling toilet back to normal.