The first step for fixing frozen pipes is to discover which section of pipe is blocked with ice. If you already know where the problem is you may move on to the next step. Two factors usually work together to freeze pipe, cold and wind. The places to look are in crawl spaces, [especially near open crawl space vents], attics, [especially near open attic vents], and outside walls, [especially where closed kitchen or lavatory cabinets keep heated room air from circulating]. It is common for pipe supplying hose valves to freeze when that pipe is run through a garage wall and the hose valve has not been winterized.
The next step in fixing frozen pipes is to examine as much of the pipe as you can see or feel, if any. See my page Frozen Water Pipes to help you know what you are looking for while you examine your frozen pipes. You want to know, if possible, if the pipe is split before you thaw it. If that has happened, only the ice itself is protecting your home from water damage. If you cannot determine whether the pipe is split you must be ever ready to turn the main water valve off while you attempt to thaw your frozen pipe.
Before you begin, answer these questions.
Once you know you can control the flow of water, look to thaw your frozen pipe.
Time is a factor when fixing frozen pipes. A pipe that is merely blocked with ice in the evening may split during the cold of the night. Hopefully you can get the pipe thawed before it breaks. If you know that the pipe is split you must turn the water off in case it thaws by itself when you are not ready to control it. Flooding in walls or ceilings made of sheet rock can cause black mold to manifest, thus creating a new problem, so do what you must. It is better to be without water for a day than to need to remove sheet rock on a wholesale basis.
When fixing frozen pipes located outside they can be thawed with warm water. Not boiling water, but warm tap water, [cold water works also but takes longer]. A common problem is discovering that the hose valve was not winterized and the now frozen hose is still attached and introducing ice into the brass. Be very careful when thawing the valve not to spill the water in the path, creating a slipping hazard when it freezes. Control the amount of spillage by holding a pail of warm water under the hose valve and dipping out of it to warm the valve. Some of the water will fall back into the pail to be used again and there will be less resultant ice on the ground. Throw salt, sand , or soil into the water you spill in the path.
Fixing frozen pipes in the attic or crawl space is more complicated. First thing, let's talk about how to do this job safely.
The tool I like to use for thawing pipe is a simple hair dryer. Here's why-
If you'll be plugging your hairdryer into a drop light cord, try to plug the trouble light cord into a GFI socket. You should find a GFI socket in the bathroom if the house meets current code requirements.
Hook your drop light (trouble light) safely away from splashing water, and don’t hold it while you work with the hair dryer.
If your light does get wet, the glass will break unless you are using a coated rough service bulb, causing the light to burn-out. For that reason alone it is a good thing to have a backup flashlight where you can find it in the dark.
Once you have your heat source safely plugged in, you're ready to begin. If it's obvious where the wind has been blowing on the pipe, start to heat that section of pipe first.
If you are able to re-establish water flow to the
fixture or fixtures that were affected by the frozen supply pipe, take
steps to keep it from freezing again.
If the pipe is already ruptured when you re-establish flow, you may find yourself getting wet. Once water is flowing you no longer need the hair dryer, so set it aside. Get it out of your hand.
Have your assistant turn off the water. If you're working alone leave the power tools where they are till the cord is removed from the power source and go turn the water off until repairs can be made.
For fixing frozen pipes made of copper or galvanized, metal that will carry an uninterrupted current, there is the thawing machine. Many plumbing companies stock this tool in the hope of returning service to and saving metal water pipes before they split. Mine cost $500 years ago! You may be able to rent one, or have a plumber bring one, but be prepared to wait your turn. And of course read the instructions carefully!