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Reasons Your Faucet Is Making a Clunking Noise

Drops of water from the faucet.

When you are running water and hear a clunking noise coming from your plumbing, it may surprise you. If the problem persists, it is essential that you determine the cause of the problem to avoid damaging your home’s plumbing system. Most of the time, you will need to call your local plumber for assistance once you have a better idea of why your plumbing is clunking.

Why Am I Hearing a Clunking Noise?

There can be several reasons for clunking and knocking pipes. The noise usually occurs when one of the following occurs:

  1. The flow of the water is stopped abruptly.
  2. When the hot water is turned on.
  3. When the cold water is turned on.
  4. At random times when the water is running.
  5. Occasionally when the water is turned off.

The frequency and speed of the clunking can also help you determine the underlying problem. When you hear the noise, ask yourself whether the clunking is a singular occurrence, continuous, periodic, or rapid.

Common Causes and Fixes for Knocking Pipes

Now that you know the reasons for clunking sounds and have narrowed down the frequency of the clunking, let’s look at common causes and how to fix the problem.

Pipes Making Noise When Water Is Turned Off

Person washing hand near white ceramic sink

Some of the common situations where you can hear a singular clunking noise and bang when you:

  • Shut a faucet off
  • After the washing machine has filled with water
  • After flushing the toilet and the tank refilling with water
  • Your sprinkler system shuts off

The most probable cause is due to the flow of the water being abruptly stopped. When the valve on the pipe is closed, the flowing water bangs into the valve. This is why this problem is referred to as “water hammer.”

Fixing water hammer problems depends on your home’s plumbing system. For example, if you have vent chambers, they are most likely filled with water. So, you would need to shut off the water main, open the highest and lowest faucets, and allow the water to drain out of the vents before turning the water back on.

If your home is newer, you most likely have a faulty arrestor that acts like a shock absorber to prevent water hammer. Replacing arrestors requires help from your plumber.

Constant Knocking Noise When Faucet Is Turned On

If your pipes constantly knock as the water runs, this problem could be caused by either having a faulty water meter or your water pressure coming into the house is too high. To fix this problem, you should check to see if your house has a water pressure regulator connected to the plumbing where the water main comes into the house.

If you do, you can turn it down until the problem stops. The water meter is the most likely culprit if it is already turned down. Contact your plumber to test the meter and replace it or install a water pressure regulator if yours is broken or you do not have one.

Periodic Knocking Noise When Running Water

A periodic clunking sound is often due to the straps and retaining clips that secure the plumbing in place becoming loose or being too tight. For example, when you run the hot water and hear knocking pipes, your pipes have expanded from the hot water, and the strap or retaining clip is too tight and causes them to bang.

Have your plumber pinpoint the location of the clunking sound. Then they can repair or replace the straps or retaining clips.

Rapid Knocking Noise When Faucet Is Turned On

If you hear a rapid clunking, banging, or knocking noise when running water, this often indicates air in pipes. The easy fix is to turn on all the faucets in the home and flush your toilets a few times to help push the air out. Then allow the water to run for about five to ten minutes. If the sound does not stop, it is time to call your local plumber for assistance.

Knocking Pipes When Water Is Turned Off

Occasionally, you will hear a knocking or banging sound randomly when the water is turned off. The most common cause is when your water heater has excess sediment buildup in the bottom of the water tank.

The sediment releases air bubbles whenever the water heater turns on to maintain the preset temperature. These air bubbles need somewhere to go, so they rise to the top of the tank or into the water supply lines. When they do, they create the banging sound.

If you have a tankless water heater but have hard water, you can also experience occasional clunking sounds from the scale and mineral deposits. The fix for this problem for tankless and tank water heaters is to have your plumber perform water heater maintenance to flush out the sediment.

Why Should I Have Knocking Pipes Fixed Promptly?

Close-up of smiling plumber fixing a faucet with blue pipes on the countertop

Clunking, banging, and knocking pipes create vibrations. These vibrations can cause all sorts of problems for your home’s plumbing system, including:

  • Causing straps and retaining clips securing pipes in place to break or come loose
  • Causing pipe connections and fittings to separate and start leaking water
  • Damaging faucets and fixtures
  • Causing water supply lines to burst and break

Suppose you are hearing clunking noises and knocking pipes in your San Antonio or Austin Metro area home. In that case, you can rely on the experienced plumbers at Christianson Air Conditioning & Plumbing to resolve the problem promptly. Contact us at 512-246-5400 to schedule an appointment today.

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