Silencing Noisy Plumbing - Eliminate Water Hammer

February 4th 2016
Silencing Noisy Plumbing - Eliminate Water Hammer

A plumbing system may produce any number of noises – but it shouldn’t. Each noise tells you something about what is calling out for correction. You just have to interpret the sound to apply the cure.

A “chattering noise” when a faucet is turned on or off, can be most annoying, and may make you think that the whole system is about to come apart at the seams. It is not usually all that serious; the problem is likely within the faucet itself.

First, check to make sure that the faucet washer is tightly screwed to the stem. If the washer is worn, it should be replaced even though the faucet is not leaking. Also inspect the threads on the back stem for signs of wear. If the stem (after being screwed back into the faucet) can be moved up and down, there is a definite indication of thread wear. Either the stem or the entire faucet should be replaced.

Pipes “rattling”, as water passed through them, may not be fastened securely. If they are accessible (as in a basement or crawlspace), install additional clamps to fasten them firmly to the joists.

On the other hand, “a ticking sound” may indicate that a pipe is fastened too tightly – cold pipes will expand slightly as hot water enters them, causing this noise if there is not sufficient expansion room.

A “whistling noise” is caused when water under pressure must pass through a point of restriction.

A common problem is with the toilet intake valve. If your toilet “whistles” as it is being refilled after flushing, try cutting down the flow by shutting the supply stop slightly (the supply stop is the valve below the toilet that governs the flow of water into the tank). Some toilet mechanisms have an adjusting screw on the intake valve itself to solve this problem.

“Water Hammer” is a loud, banging noise that occurs when a faucet is shut off quickly. Behind every fixture, there should be an air chamber which provides a cushion of air to absorb the force of the rushing water – and the accompanying noise. There are many different types of air chambers, in addition to the simple pipe and cap type, but all work on the same principle. If the chamber becomes filled with water, its cushioning effect is compromised.

Eliminate Water Hammer:

Try the following steps to get rid of the airlocks within your plumbing that can cause water hammer: (Banging pipes or pipes that rattle.)

1. Shut off the main water supply (there is usually a shut-off valve right at the location where your water service enters your home).

2. Go throughout the house and turn on all your water faucets including any outside faucets.

3. Flush all your toilets.

4. Turn your dishwasher to the fill cycle.

5. Turn your clothes washer to the fill cycle.

6. Shut off the water supply to your hot water tank.

7. Leave the system for about 2 to 3 hours to allow the water to completely drain (to the lowest point).

8. Turn the water back on at the main water supply valve.

9. Wait until all the taps have water running at full force.

10. Turn your dishwasher off.

11. Turn your clothes washer off.

12. Turn on the water supply to your hot water tank.

13. Start shutting off the water faucets beginning with the faucets that are the highest (within the home) and the furthest away from the main water shut-off and work your way to the faucets that are the lowest and closest to the main water shut off valve.

Note: The toilets tanks will fill up and shut off on their own.

Another tip: Never tighten water pipe clamps on floor joists. They should be loose in order to allow pipes to expand and contract.

Your water hammer should now be gone!