Thawing a frozen water line in your home is easy when you have a little patience and a mild heat source. Frozen pipes are likely to burst if heated too fast, so slow and steady is the best plan of action.
Step 1: Turn on the faucet along the frozen line. If the pipe is not completely frozen, the slow trickle of water may be all that is needed to remove the blockage.
Step 2: Shut off the water supply to the frozen line. If the line is not equipped with an individual shut off valve, turn the water off at the water meter or well pump.
Step 3: Inspect for damage by running your hand over the pipe. Look for cracks or breaks along the length of the pipe. If the pipe is damaged, collect the supplies necessary to repair it before thawing the blockage.
Step 4: Slowly warm the frozen pipe using a mild heat source such as a hair dryer, heat lamp, water-resistant heating pad or space heater. If the pipe is not readily accessible, heating the ambient space near the pipe should also do the trick. When heating a frozen pipe, work from the faucet back toward the blockage. This will allow any steam to escape and reduce the risk of the pipe bursting. Wrapping the frozen pipe with a towel and pouring hot (not boiling) water onto the towel will also create enough heat to thaw the blockage. As the towel cools, pour additional hot water onto it until the pipe is thawed. Never pour boiling water directly onto a frozen pipe, and never use an open flame to thaw a pipe.
Step 5: When the blockage is eliminated, turn the water supply back on and allow water to run though the pipe until it is flowing freely.
Step 6: Install heat tape and pipe insulation to protect the line from freezing again or check with a plumber about relocating the troublesome pipe altogether.