The loud pounding noise that comes from your pipes, washing machine or dishwasher when the water shuts off is more than an annoyance. Your plumbing could be suffering major damage because of water hammer.
When you open your faucet or turn on the shower, the water is rushing to get to the source as quickly as possible. When you no longer need the water flow, you turn off the fixture, causing the rushing water to slam into the closed valve. The thud that you hear is the hydraulic shock created by the water crashing to a sudden stop. The impact can create plumbing problems over time, including damage to appliances, loose fittings or broken pipes.
The slamming of the water into the closed valve is sometimes powerful enough to jolt your pipes, causing them to move slightly. If the pipes aren’t securely fastened to the joists, the pipes could clang into your walls, creating more damage and an even louder noise.
How to stop water hammer
Homes built over the past few decades are equipped with a piece that helps fight against water hammer. Air chambers are installed just behind a valve. The short, vertical pipe is designed to hold air that serves as a shock absorber when water is suddenly shut off.
Over the years, the air chambers can fill with water, making their presence less effective. To restore the air to the chambers and remove the water, start by turning off your home’s main water valve. Next, open faucets in your home on each level. The remaining water will exit the system, refilling the chambers with air. Turn the main water valve back on and test your noisy faucets or appliances.
In older homes without air chambers, it may be worth the investment to have them installed. They last for decades and you’ll pay less for preventative maintenance than with a plumbing emergency call because of a burst pipe. Another repair option is the water hammer arrestor. Installing these units throughout your home will greatly reduce the sound and damage caused by water hammer. While the arrestors won’t fill with water, they do wear over time and will need to be replaced.
Causes of water hammer
If your air chambers are working properly but you’re still experiencing the sounds of water hammer, check your home’s water pressure level. High water pressure could be the culprit behind the banging. A water pressure gauge is inexpensive and easy to use. Screw the piece onto one faucet in your home. Ensure that no other fixtures are running water and turn the faucet on. The gauge will measure your water pressure, which should sit between 50 to 80 psi. Anything above that level should be addressed.
Your local utility company may be able to help by sending a worker to your home to reduce the pressure level near the water meter. If that doesn’t help, call a professional plumber to have a water pressure regulator installed. The part itself is about $60 to $70, but you can expect to pay around $250 or more for professional installation.
Don’t ignore the sound of water hammer in your home. The continuous slamming of water against your valves could make for costly repairs in the future. Test your water pressure level and call the pros if you need to make changes to your plumbing.