groaning water pipes?
Answers:
sounds like you have air in your pipes they need to be "bled" to get the air out ~ if they are old and made from galvinized steel or copper, maybe you should consider replacing all of them to PVC piping. It's a pain but in the long run it's worth it.
Other answers:
It's a form of vapor intrusion. somewhere in the house, usually at the plumbing system's highest point, there is trapped air. When you turn on the tap the pressure is released. When you turn it back off it is supposed to re pressurize very quickly. However when there is a section of pipe that has air trapped in it, it repressurizes much more slowly because you're compressing air. Hence the groaning sound. Try this. Start upstairs and open every faucet in the house and outside until all of them are on. Let 'em run for about ten or fifteen minuites. Then shut them all off one at a time. This should re-flood or "re-prime" the system and the noise should go away. If it doesn't, then your problem is bigger than you and you should call a plumber. Good Luck!!
It's a form of vapor intrusion. somewhere in the house, usually at the plumbing system's highest point, there is trapped air. When you turn on the tap the pressure is released. When you turn it back off it is supposed to re pressurize very quickly. However when there is a section of pipe that has air trapped in it, it repressurizes much more slowly because you're compressing air. Hence the groaning sound. Try this. Start upstairs and open every faucet in the house and outside until all of them are on. Let 'em run for about ten or fifteen minuites. Then shut them all off one at a time. This should re-flood or "re-prime" the system and the noise should go away. If it doesn't, then your problem is bigger than you and you should call a plumber. Good Luck!!
I think that if you install a surge pipe in your system it will stop the noise.
A surge pipe is a vertical section of pipe at least 18" long (longer if there is room) teed into your system and caped at the top end.
The pipe is full of air when it is installed, so when the water is turned on the air in the pipe is pressurized to the same pressure as your system. When you open a tap there is a pressure drop in the system and the air in the pipe expands. When the tap is turned off the air in the pipe acts as a cushion and stops the sudden pressure surge.
You can test this before doing any modifications by turning the tap off very slowly.
There is no air in the pipes. Probably what is happening is that when you run the hot water, the pipes heat up as the hot water travels to the faucet. AS they heat up, the hangers that hold the pipes up tight to the floor or whatever they are attached to will groan do to expansion of the pipe due to the hot water. The thing to do to fix it is located the noise in the house, find the water pipe, and loosen it up a bit. That will stop the noises in the house! Good luck!!