pipes under house sound like a machine gun

[davemchine]

When I flush the toiled in the 2nd bathroom the pipes vibrate so violently it sounds like a machinegun is going off. I've lived here 10 years and have never experienced this. What could it be?

Dave

[rgG]

Here's a link that might help.

http://www.factsfacts.com/MyHomeRepair/PipeNoises.htm

[modelamac]

Something has changed if this has never happened before. Some new plumbing/water heater/etc., or some pipes have come loose from their hangers.

[OWC Jamie]

Water hammer (as in rgG's link)
I've seen two kinds of hammer arrestors.
The ones you buy that have litle 'air bags' in them, should be replaceable if they've gone defective.
If you have them, they should be in a convenient place to replace them.Often in the back wall of a closet or wherever your pipes make the verticle run to upstairs.
Most often put near the device that would cause hammer in the first place, like a washing machine.
Home made ones , a 6 to 12 inch 3/4 pipe on a 1/2" system, that should be full of air to absorb the shock, but can become water logged.
If you have home made ones, draining the water from the lines will remove the water from the absorbers, you'll be back in business when you turn the water back on.
That would be the first thing I would try, as it's simplest. Drain water and turn back on.

Your pipes could also be loose from broken/loosened hangers.
If they'rs just routed through holes in wood rather than strap hangers, a bit of insulating foam will help.

Closing the valve to the toilet fill some (lower flow) might help, but they might just groan instead.
Toilet innards valve might be causing it if it's "bouncing" closed.
Higher street/well pressure may be exaserbating a problem you've always had.

[cbelt3]

yep- water drain is the main solution.
Shut off your main water valve
Find the LOWEST tap in your house
Open it
Now go up your house and open ALL the taps (even flush the johns, hot water too, open the outside taps, etc.

Now go back down and turn on your water supply. Then go back up and close taps from the bottom up.

Once you're done, no more water hammer.