• Pipes and wiring have to fit in small spaces.plumbing image by Inger Anne Hulb?|kdal from Fotolia.com
  
  Water moving through a home's water pipes can cause a variety of puzzling noises. When you hear the noise only when using hot water, the problem is usually caused by copper pipes, which expand as hot water goes through them making them rub against wood or metal, such as studs, joists, or the straps and brackets supporting the pipes. This is not the same as water hammer, which is caused by fluctuating water pressure causing the pipes to vibrate.
  
  

Ticking

• Secure those pipes and give them room to expand and contract before putting up the walls.framed plumbed and wired image by Scott Patterson from Fotolia.com
  
  Hot water causes cool copper pipes to expand, rubbing against whatever they touch; when the pipes cease to expand, the ticking should stop. You might try lowering -- slightly -- the temperature setting on your water heater in case that helps, suggests Richard Trethewey of This Old House.
  
  

Creaking and Cracking

• Turning faucets -- or showers -- on and off can cause noises in the plumbing.faucet image by Laura Dynan from Fotolia.com
  
  As the pipe cools after expanding, it contracts, thus creating creaking and cracking sounds. Wood amplifies these noises, as do copper pipes -- more so than plastic ones. Installing plastic pipes could be a better choice in some cases.
  
  

Rattling

• Listen to your pipes when water is running.detail of faucet and sink with running water image by nextrecord from Fotolia.com
  
  Rattling may be caused by a ball in the energy saving device known as a nipple in a hot water heater; the rattling begins when you turn on a hot water faucet. It could also be caused by one pipe touching another pipe or a loose faucet washer. Though the pipe occasionally may rub hard against another pipe, stud or bracket, it usually shouldn't result in a leak.
  
  

Other Causes

• Pipe with clamptuyau cuivre image by Claudio Calcagno from Fotolia.com
  
  A build up of sediment, which reduces the space for the water to flow, may cause whistling. Shutting off the water can cause a water hammer. If the noise is caused by the dishwasher, possibly the copper pipe is hitting something or the dishwasher isn't securely fitted.
  
  

Possible Fixes

• Another type of clamp.bague de serrage image by Unclesam from Fotolia.com
  
  Since loose pipes or pipes crowded into too small a space or with insufficient supports usually cause noisy hot water pipes, you would have to open the wall up, which is usually a costly and messy fix, to add foam insulation, make more space for the pipes or replace metal hangers or clamps with plastic ones.