We live in an old house and some times the pipes freeze.The easiest way to thaw a pipe is to use a hair dryer. It cantake awhile, but the risk of burning down the house or hurting the pipes is small.
There is one pipe that freezes when the temperature is less than -5.After years of trying to fix it and prevent it from freezing and thawing it out we figured out that a three foot piece of heat tape solves the problem.
One year we had a drain freeze because if a dripping faucet. That one was an easy fix but until we could fix it we put a bowl in the sink to catch the dripping water. We have had some brutally cold weather in the last week and even colder weather is on the way.
There is still time to head to the home improvement store and buy some heat tape. It is easy to install and inexpensive.
If your home is on the market and you have had problems with freezing pipes it needs to be disclosed on the sellers disclosure.