Locate and insulate pipes most susceptible to freezing—typically those near outer walls in crawl spaces or in the attic. Insulation made for this purpose is available at hardware stores.
Wrap the pipes in UL-approved heat tape.
Seal any leaks that allow cold air inside where pipes are located.
Disconnect garden hoses and shut off and drain water from pipes leading to outside faucets. This reduces the chance of freezing in the short span of pipe just inside the house.
When the weather gets cold
Let cold water trickle at night from the faucet farthest from the hot water tank.
Open cabinet doors to allow more heat to get to uninsulated pipes under sinks.
Make sure heat is left on and set no lower than 55 degrees. If you plan to be away, have someone check the house daily to make sure the heat is still on.
If the pipes freeze
Make sure you and your family know how to shut off the water in case the pipes burst.
Never try to thaw a pipe with an open flame or torch.
Always be careful of the potential for electrical shock in and around standing water.