How do I get rid of a "water hammer" in my plumbing?

Question

Every time we flush the toilet, and just about at the point when the tank is refilled, there is a terrible thumping and rattling from the pipes. If I quickly turn the water on in the tub it goes away, so I've been flushing and then turning on the water in the tub as a pre-emptive strike, and that seems to work, but the rest of the family isn't as diligent and it gets so loud I'm afraid something is going to happen to the plumbing. Any advice, suggestions, insights?

Answer 1

The link below will give you great and complete information on the "water hammer" problem. It is a real problem and can cause failure of the water pipes and other appliances in the system. A simple solution is to reduce the water supply by turning down the supply at the street or replacing the washing machine hoses with new longer ones that can help to absorb the shock. In aviation, we have accumulators or vertical pipes filled with air to absorb the shock, but this might not be allowed by local codes. It may be a good idea to replace the washing machine hoses anyway as they can fail and flood your house. I just happened to be near my washer when a hose broke or our house would have been flooded.
You can get a water hammer arrester at just about any plumbing supply store. At your local hardware or home store look for a pre-packaged water hammer arrestor that attaches to a standard washing machine cold water outlet. The ones I have seen come in one of those clear plastic display packages, and look like a copper tube with hose connections. Check the return policy of the store before you buy it, will they take it back if it doesn't work? Make sure you keep all the packaging. Install it per the directions on the package. If you are installing it on a dishwasher fill, you will probably need some adapters to make it fit. If it doesn't work, remove it and return it.

Answer 2

What you want to do is make a water hammer not get rid of one. Since the toilet would be cold water just cut into the line and put in a tee, what I do is it is is 1/2 inch I get a tee that is 1/2 inch on two end and branches to 3/4 on the side. I then solder in a one foot long piece of copper tubing with a cap on the end. That will get rid of the water banging your pipes. It all depends if you have PVC or galvanized, then instead of copper you need to make your hammer of that material.

Answer 3

I am with Dylan on this one, as he says its not an airlock as if it was either the water would not come out of the tap at all or it would be a dribble.Its almost certainly being caused by a ball valve that probably needs a washer. The noise is the pipework vibrating very rapidly causing a 'hammering'

Answer 4

Water hammer is usually caused by air in the pipes, but this sounds like the valve in your toilet is bad. I would change the valve in the toilet first and see if this cures the problem. It will harm your plumbing eventually if you allow it to continue.

Answer 5

your toilet tank valve is shot. the rubber gasket that closes the water when the tank is full is not shutting all the way making that load sound. when you turn on another faucet, it relieves the pressure, allowing the water to shut off in the tank. the only thing you can do is replace the whole valve as there is no replacement rubber gasket you can get to solve your problem.

Answer 6

Get a fill valve that closes gradually. You can buy water hammer arrestors but they can be hard to retrofit into exinting plumbing.

Answer 7

They have what they call water hammer arresters, a device that carries a air charge that acts as a shock absorber. see the one that can hook to the supply line.

Answer 8

They make clamps to bolt the pipes to the wall.

Mike Honeycutt