ThoroSpec

Winter Home Maintenance Tip #4: Prevent Frozen Pipes -
Remember the three central causes of frozen pipes? Quick drops in temperature, poor insulation, and thermostats set too low. You can prepare by protecting your home during the warmer months. Here’s how: Insulate pipes in your home's crawl spaces and attic, even if you live in a climate where freezing is uncommon. Exposed pipes are most susceptible to freezing. Remember: The more insulation you use, the better protected your pipes will be.
Heat tape or thermostatically controlled heat cables can be used to wrap pipes. Be sure to use products approved by an independent testing organization, such as Underwriters Laboratories Inc., and only for the use intended (exterior or interior). Closely follow all manufacturers' installation and operation instructions.
Seal leaks that allow cold air inside near where pipes are located. Look for air leaks around electrical wiring, dryer vents, and pipes, and use caulk or insulation to keep the cold out. With severe cold, even a tiny opening can let in enough cold air to cause a pipe to freeze.
Disconnect garden hoses and, if possible, use an indoor valve to 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.