The knocking sound you often hear when you flush your toilet may seem ambiguous, but it’s not. Does it sound like someone is knocking on the other side of the wall? If so, the knocking sound results from water pressure spikes within the supply pipes.
If not corrected, water will continue crashing into the valves and side walls and eventually loosen straps and joints that hold the pipes in position.
What the Knocking Sound From Your Toilet Means
Soft Knocking or Tapping Sound
If you hear a soft knocking or tapping sound from your toilet, chances are high that it may be due to a faulty flapper. A flapper is the rubber seal that closes the flush valve, keeping water in the tank, and opens up when you flush your toilet.
The flapper doesn’t seal well when it is faulty and leaks water down the drain to the bowl, creating a bumping or tapping sound.
What to Do
The only solution, in this case, is replacing the faulty flapper.
- First, scoop water out of the tank into a bucket to access the flapper at the tank’s bottom.
- Next, release the flapper’s chain from the lever arm and remove the old flapper.
- You’ll then clean up any debris or mineral deposits that may be present around the drain’s edges.
- Afterward, attach a new flapper chain to the lever arm, and place the flapper in its original position at the bottom of the tank.
Water Hammer
A water hammer is a term describing the forceful impact of water as it crashes within the pipes. The water we use in our homes is usually under high pressure of 40 to 60 PSI, or even more. When you open a tap, water rushes out immediately.
What happens when you close it?
The answer is that the water on the other side of the tap (within the pipes) remains under high pressure. When a valve opens, say after flushing your toilet, water rushes out and into the tank at high pressure. When it reaches a preset level, and the automatic valve shuts abruptly, the high-pressure water has nowhere to go and crashes into itself.
The kinetic energy is then converted to sound energy, as you’ll hear loud knocking sounds or “water hammers”.
What to Do
It’s evident that the knocking sound isn’t an issue of immediate concern. However, be wary if you have older plumbing in your home, as prolonged knocking can loosen joints and fittings supporting the water supply lines.
Consequently, here’s what you ought to do.
- Locate and turn off the main water shut-off lever to your house.
- Open the highest faucet in your house and drain water from the lowest faucet.
- Next, flush all toilets in your house and run the washing machine and dishwasher long enough to drain them. Usually, this step takes a few minutes.
- Drain the water hammer arrestor if it has some water in it too.
- Afterward, close the lowest faucet (the one in the basement) and turn on your water supply. Here, the top faucet will spew out water briefly. Turn it off when the spews turn into a constant stream.
- Give time for the toilets to refill if they’re still doing so.
- Finally, flush the problematic toilet to see if the issue is cleared.
Can Water Hammer Damage Your Toilet?
Yes, water hammer can damage your toilet. left untreated, there are many ways it can cause damage.
Worn-Out Fill Valve
The repeated pressure surges caused by water hammer can wear out the toilet’s fill valve more quickly, leading to leaks or constant running.
Cracked Tank or Bowl
In severe cases, the force of water hammer can stress the porcelain tank or bowl over time, especially if the toilet is older or already has hairline cracks.
Loosened or Damaged Connections
Vibration from water hammer can loosen supply line fittings, leading to small leaks or even sudden bursts if a hose fails.
Strain on Shut-Off Valve and Supply Line
The shut-off valve behind the toilet and the flexible supply hose are often the weakest points. They can fail prematurely under repeated pressure shock.
Pipe Joint Stress
Although not limited to the toilet itself, repeated water hammer can also cause soldered or threaded joints near the toilet to weaken or leak over time.
Final Remarks
If the above procedures don’t work or do so temporarily, your plumbing may have other serious issues. Therefore, consider calling in a plumber for assistance before they get out of hand.
Continue Reading:
Why Does My Toilet Squeal When I Flush?
Why Does My Toilet Make Noises When Not In Use?
What Causes a Toilet to Make a Vibrating Noise?
Sources
https://bfplumbingbayarea.com/blog/why-are-my-pipes-knocking-when-the-toilet-is-flushed/
https://customairinc.com/blog/ever-wondered-knocking-sound-pipes