Turning your faucet on and hearing a clunking noise can be a surprising and even alarming experience. It’s important to have this type of problem checked out as soon as you can to make sure you’re not at risk of damaging your pipes.
Water pressure problems, venting, old fixtures and water hammers are all potential reasons why this happens. Read on to diagnose why your pipes are making a knocking noise when you turn your faucet on or off.
Continuous Pipe Thumping
You could have one of two problems if your faucet makes a knocking noise continuously while the water runs:
- You have a faulty or inadequate water meter.
- Your water pressure is too high.
A plumber can diagnose either issue. When your water pressure becomes too high, it stops flowing in an orderly stream and becomes turbulent. The water traveling through your plumbing violently sloshes against your pipe walls.
Use a pressure gauge to check your home’s water. Your pressure should be between 40-80 PSI. If it isn’t, you may need your pressure-reducing valve adjusted or replaced at your main water supply. A professional plumber can identify and remedy the issue.
Periodic Pipe Thumping
If the clunking noise only happens on a periodic basis, the reason may be that the straps that hold your pipes in place are too tight. Pipes expand and contract – they expand when they are warmed by hot water and contract when they cool down. Usually, if this is the issue you won’t hear the noise after a couple of minutes.
This expansion issue can be especially prominent issue if you have CPVC pipes. CPVC pipes are often used for hot water lines and will expand or contract with temperature. They are cream colored and may have a “CPVC” stamp on them. Have a plumber loosen the straps and pipe openings around your pipes to resolve the issue.
Rapid Pipe Clunking
If you hear a rapid clunking noise when you turn on the faucet that could mean air is trapped in your pipes. Try turning on all of your home’s faucets at once and then flushing all of your toilets. Wait for five minutes or so and give the water time to push out the air. If the noise does not disappear after that, then call a professional to have your pipes checked.
Pipes Knocking When Faucet is Turned Off
If your pipes make sounds or shake when you turn your faucet off, you’re probably experiencing a “water hammer.” A water hammer occurs when high velocity water traveling through your plumbing suddenly crashes into a closed valve. You might observe this when your turn a faucet off, when your toilet tank stops refilling or when your washing machine fills up.
Older homes (pre-1960) are often equipped with “T-shaped” air valves that help cushion the impact of water hammers by giving the stopped water a place to back up. Over time, these valves can fill with water and lose their function.
If you have an older home:
- Turn your water supply off at the main line.
- Open the faucets at the highest and lowest points in your home and run the water out.
- Close the lower faucet and turn your water supply back on.
- Let the upper faucet run until it stops sputtering.
The air in your valves should be restored.
If you have a newer home with water hammers, you may need to install water hammer arrestors. A water hammer arrestor is a small, spring-loaded device that acts as a shock absorber for rushing water. To install a water hammer arrestor, you need to cut the pipe as close to the clunking point as possible and solder in the arrestor. A professional plumber can perform this more demanding task if you’re not comfortable splicing pipes.
Stop Your Faucets from Clunking, Knocking and Shaking
There’s no need for you to have to put up with a faucet that makes a clunking noise. Call Benjamin Franklin Plumbing Dallas at 972-301-8387 or fill out our quick contact form for fast service. We keep pipes healthy in Plano, McKinney and Dallas.