Water Hammer

Noise, Knocking Pipes and Water Hammer

QUESTION: My mom’s home was built in 1959. For the last year, we have heard a loud knocking any time the water from one of the kitchen, bathtub or bathroom faucets is turned off after running. It knocks four or five times and then stops. It doesn’t happen when the toilets are flushed or when the dishwasher or clothes washer are run. We have never seen evidence of a leak. Can you shed some light on what is causing the knocking? Monica Thacker, Carmichael

ANSWER: “What you are describing is called ‘water hammer,’ but I am afraid I just don’t have enough information to make an accurate diagnosis,” says Vince McDonald of McDonald Plumbing, Heating and Air Conditioning in Sacramento. “It is odd that the noise happens with all those faucets but not the dishwasher or washer, and that it makes noise after, rather than during, the operation of the faucets. The list of possible causes includes loose faucet washers, a bad fill valve in a toilet, and thermal expansion and contraction of the piping system. I don’t think the noise is cause for alarm. It is not likely that the problem will cause damage to the home. This sounds like a good one for an informed plumbing contractor to visit the site in person,” he says.

More Information and Solutions for ‘Water Hammer’ In Your Sacramento Home or Office

Water hammer or hydraulic shock is loud, annoying, and can be detrimental to your pipes. Good news, fixing this problem in your Sacramento home is easy. Hydraulic shock or water hammer is the loudest and most common problem plumber’s face in older Sacramento homes. When you hear it it’s because the Sacramento home has high water flow rates when a water valve or faucet is shut off to fast.


The older homes in Sacramento have an air chamber on each hot and cold water line near the inlet valve or faucet. The air chamber basically acts like a shock absorber for water flowing under pressure at high speeds. Water doesn’t compress but air does, so the air chamber allows a temporary place for the water to expand and soften the blow of the shock wave when the faucet is shutoff to quickly. Most often air chambers are built on-site by the plumber or plumbing service provider and placed at the faucet’s water supply. An air chamber is generally a vertical pipe about 12 inches long that is the same diameter as the water supply pipe. If you have a water filled air chamber it can be easily fixed by draining and recharging the plumbing system. Contact McDonald Plumbing, Heating and Air Conditioning in Sacramento to Fix Your Loud Pipes and Plumbing System Today! Since 1957 McDonald Plumbing, Heating Air Conditioning has been providing water hammer repairs to Sacramento residents and businesses. We also serve Sacramento and the surrounding communities with a full line of plumbing, heating and air conditioning repairs such as tankless and regular water heater installation and repair, air conditioning installation and repair, home energy audits, home comfort systems, sewer and drain cleaning, sewer and water line repair and repair of slab leaks.

Sacramento, CA

Sacramento is the capital city of the U.S. state of California and the seat of government of Sacramento County. It is at the confluence of the Sacramento River and the American River in the northern portion of California’s expansive Central Valley. With an estimated 2011 population of 477,891, it is the sixth-largest city in California and the 35th largest city in the United States. Sacramento is the core cultural and economic center of the Sacramento metropolitan area which includes seven counties with an estimated 2009 population of 2,527,123. Its metropolitan area is the fourth largest in California after the Greater Los Angeles Area, San Francisco Bay Area, and the San Diego metropolitan area, as well as the 27th largest in the United States. In 2002, the Civil Rights Project at Harvard University conducted for TIME magazine named Sacramento “America’s Most Diverse City.


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