Why are Pipes Squealing When I Flush?

Ever hear a strange sound coming from the sink or behind the walls and wonder why the pipes are squealing when I flush? Do you find yourself not knowing the cause yet alone how to fix it? Banging, moaning, and squealing noises usually indicate an issue with the toilet that needs addressing. You can fix most issues easily fixed once you determine the source of the problem.

Pipes squealing when I flush

If the squeak occurs while the tank is refilling and you have an older toilet, the ballcock valve may need readjusting. A broken fill valve causes squealing with flushing in newer toilets and is a little more serious. It can lead to significant water damage if not repaired quickly.

What Causes a High-Pitched Squealing or Whistling Noise?

Solution #1

If you notice after flushing that the toilet generates a high-pitched noise while the tank is refilling, refrain from panicking. The pipe noise may result from an old ballcock valve (may also be called the float valve).

The fix is inexpensive and quick. Most of the time, you only need to adjust the ballcock mechanism. Most people chose to replace the entire thing because the cost is so cheap, but you can adjust it yourself and spare the expense.

Plumbers can resolve the issue quickly and get rid of the creepy noise. This issue will arise with ballcock systems, and experts recommend that homeowners upgrade to a fill valve which will save them time from going through the same exercise at a later date.

However, even upgrading to a fill valve may not always solve the problem. Even a fill valve, after time, can make the same sound.

How to Fix it

Generally, older toilets have ballcock fill valves that require placing from continued use. Squealing and groaning or if the handle feels light when you flush, or it won’t flush at all, are all indicators it needs replacing.

  1. Turn off the water, then flush the toilet. Once the tank is empty, go underneath, and put a bucket below the retaining nut. Take out the ballcock retaining nut by using an adjustable wrench. Then remove the old ballcock assembly.
  2. Align the replacement ballcock valve. Attach a cone washer to the new ballcock tailpiece in the tank opening. The float arm socket should align in the float arm, which will pass at the rear of the overflow pipe. Screw in the float ball to the float arm.
  3. Attach the refill tube. Clip/bend the refill tube. The tip should be inside the overflow pipe.
  4. Reattach the supply line and turn on the water. The mounting nut and supply-line coupling nut should screw to the ballcock tailpiece. Tighten it by using an adjustable wrench. Then, turn on the water and examine for leaks. Avoid over-tightening the mounting nut as it may crack the toilet tank.
  5. Adjust water tank levels until they are 1/2” below the top of the overflow pipe. You can align it with the marked full line inside the tank as well.

Solution #2

The toilet tank is at the back of the toilet. Its purpose is to act as a holding container for water used for flushing waste, and it has a fill valve. This device regulates the amount of water that goes back into the tank after flushing.

The tank has a float that rises and falls with the water tank. When it falls, the valve opens to allow water to flow back into the tank. When it reaches the preset level, the valve closes, preventing water from entering the tank.

A toilet whistle after flushing or during random times of the day can be caused by a broken fill valve. As the valve ages, parts can deteriorate, causing whistling, hissing, or squealing sounds coming from the toilet.

It can also cause the tank to vibrate, causing several strange sounds coming from the toilet.

If the valve is whistling, you must replace the valve immediately. If not, it will fail within a short amount of time. Simple adjustments can eliminate the noise, but only for a short duration. It will fail very soon.

Ignoring the problem can generate increases in water consumption which means homeowners will be paying more on their utility bills. Fill valves can run either in intermittent intervals or continually, wasting hundreds to thousands of gallons of water yearly.

Fill valve replacements are easy. But, if you don't do them properly, you may face thousands of dollars in repairs due to water damage.

Man checking toilet flush

How to Fix It

Worn-out fill valves cause leaks and wear on the other components/parts of the system. It can also cause a squealing sound while flushing.

  1. Disconnect the water supply line. This valve is usually on the wall behind the toilet. It should be off and drained before installation. Shut off the water by turning off the shutoff valve clockwise.

Flush the toilet to drain the tank. Hold the lever down to drain out as much water as you can. Large cups or buckets often catch water as you are draining it. Then, remove the lid and float ball from the tank. Remove excess water with a sponge or towel. Disconnect the previous supply line.

  1. Get rid of the old fill valve with adjustable pliers/wrench by taking out the valve nut. The valve nut locks the valve body in place in the toilet tank. Take out the fill valve from the toilet tank. Then, wipe the tank by using a micro-fiber cloth to remove water, debris, and stains.
  1. Adjusting the new fill valve involves adjusting the toilet valve’s height, so the marking located on the top of the valve is one inch above an overflow tube.
  1. Place a new fill valve in the tank and connect the supply line again. Put the valve shank into the fill valve. Place the base of the fill valve in to the tank opening. Press on the shank. Tighten the locknut as far as you can to seal the valve. Reconnect your supply line, sealing the flow.
  1. Place the refill tube inside the tank and angle it to the overflow holder.
  1. Turn on the water supply, then flush the toilet to test it. Allow the tank to fill. Adjust the water by squeezing the adjustment clip, moving the float up and down.

The cause of a squealing or whistling sound when you flush is usually the cause of a faulty ballcock valve (older toilets) or fill valve (newer toilets). After repeated usages, they break down due to wear and tear on the equipment.

The fixes are relatively simple. However, if you are not comfortable doing them, please hire a qualified plumber for the job, eliminating the potential of repairing water damage should something go wrong when trying to fix your noisy toilet.

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