The Science of Water Surges

• A surge in water is caused by a sudden change in water pressure, usually at the inlet or outlet of the pipe. When a surge occurs, water travels down the pipe at the speed of sound. It then travels back when it hits an obstruction. The wave continues to travel back and forth, creating tremendous water pressure, until it tapers out.
  
  

Pumps and Valves

• There are two common causes of a water surge: a valve somewhere in a pressurized water system being opened or closed too quickly or a pump suddenly turning on or off, perhaps from a power failure. The problem occurs most frequently in copper pipes, but it can affect all types of pipes. The problem is magnified in older pipes that have become unanchored, thus vibrating more.
  
  

Other Sources

• There are other, less common sources of water surging in pipes. If the water source from your home is a well, the surging can occur from the well water pump. Another possible cause is that the water hammer protection device installed in your washing machine, toilet, faucet or dishwasher is worn out or defective.
  
  

Solutions to the Problem

• There are several solutions to protect your pipes from surging water. First, if you notice that the surging always comes when you run a particular appliance, such as a washing machine, install an automatically closing valve or an air chamber in that specific fixture. Both of these solutions will cause the valve to close slowly to prevent surges. Another option is to install air valves in your water system. These relieve water pressure inside the pipes.