water pipes banging

[ctgo4it]

I inspected a house today, when the hot water is opened there is a terrible banging in the pipes, I guess air? What are recommendations to give for this?

Thank you

[chicago]

That is known as water hammer.

http://www.wisegeek.com/what-is-water-hammer.htm

[Les]

usually $25 fix or per bob villa, $10 and you can do it yourself.

[Neal Lewis]

Do you hear the noise when the valve is being opened or closed? If you get the noise when opening a valve, I would say the valve washer is loose and rattling against the seat.

[ctgo4it]

I wanted to say it's water hammer, but it's not when the valve is bbeing opened or closed. It happens while the water is running. The water would be queitly flowing, then the banging starts till the water is shut off

[chrisprickett]

Is the water supply coming from a well? Could be getting air in the holding tank. When I lived in Stamford, CT, we had the same issue. Every couple of months I had to bleed the air from the tank, and then it would go away for awhile.