Don’t panic. Frozen pipes can be thawed and water flow restored before water lines burst. That’s the good news. If you fail to thaw your water lines prior to them bursting, you’re in for a significant problem.
Anticipate your lines will freeze when temps go below 10 degrees Fahrenheit. If a good wind is blowing, that factor also contributes significantly to the problem. Even the best construction leaves gaps where air penetrates the foundation and can freeze your plumbing. Installing heat tape on your supply lines, usually in your basement or crawl space, can save endless hours of work and expense. Speak to a licensed and insured plumber about getting this pre-emptive fix to freezing water lines in place.
By the way, many find the hot water line freezes before the cold line. That may be true, but not because hot water freezes faster than cold. Most often, when hot water lines freeze first, it’s due to the fact the line is closest to the outside wall and extreme temperatures.
Short of properly installed and maintained heat tape, leave your water dripping at the faucet. Leave your toilet handle engaged so that the supply line stays open and running. Leave your tub and shower dripping a bit as well. Make sure the drip. drip, drop is fast enough to prevent the lines from freezing. You’ll have to gauge how fast using some common sense and judgment.
Drains can freeze if the dripping water isn’t fast enough. In a deep freeze, thawing drains can be even more problematic. I’ve poured gallons and gallons of boiling water down drains and still not opened up frozen drains lines. I now take old time milk can (a 5 gallon bucket may do the trick), let the water drip, and empty the water into the toilet. That way my drains don’t freeze up.
Using a hair dryer or portable heater also works to thaw pipes or other types of water supply lines. It’s best used where you suspect the ice has formed. Diagnosing just where that freeze up can be difficult—especially if you are not familiar with a home.
Often, a hair dryer or portable space heater under the sink will thaw supply lines. Be careful to use any heat source wisely. Space heaters can draw a lot of electric current. If left unattended, you could start a fire.
Plumbing professionals have experience in clearing frozen pipes and drains. Call one immediately. The cost is well justified. If you are not the DIY sort, for sure—call in help and get your situation under control before the water lines break.
As a disclaimer: I am not a plumber or expert. I am a home owner that has been through a number of situations requiring pipe thawing. Use these suggestions at your own risk and don’t burn your place down by using torches, heat guns, heat lamps, space heaters, hair dryers, or other heat sources unsupervised or unattended.
Best Idea is—Call your local licensed and insured plumber to get the problem solved.