how to thaw frozen pipes underground

How to Thaw Frozen Pipes Underground

Waking up to a wintry morning can be enchanting. You turn on the faucet, hoping to start the day with warm coffee or tea, only to discover that there’s no water! When temperatures drop below 20°F (-6.667°C), it can be common for non-insulated pipes to freeze. If this is your situation, the frozen pipes must be dealt with quickly, otherwise, they risk bursting. Keep reading to learn how to thaw frozen pipes underground.

How Do I Know If My Pipes Are Frozen Underground?

You know your pipes are frozen, but which ones? To determine whether your underground pipes are frozen, you must first rule out frozen pipes inside of your house. Indoor pipes are much easier to identify, simply because you can see and feel them. If you see a layer of frost on the indoor pipes or they feel cold to the touch, these are signs that you’ve likely found the issue.

To thaw frozen indoor pipes, you can turn up the temperature on your thermostat or use a strategically placed heat lamp. However, if you cannot locate any frozen pipes indoors, your underground pipes may be frozen. This is a much more complicated fix, but it can be done yourself with just a few supplies and some simple instructions!

DIY Method for How to Thaw Frozen Pipes Underground

To thaw frozen pipes underground yourself, there are some supplies you’ll need to gather first. All of these should be fairly easy to find at your local hardware store. You’ll need: 

  • Gate valve
  • Nylon hose (125 feet long)
  • Large storage container (at least 5-gallon capacity)
  • 5 gallons of water
  • Pond pump

Once you’ve collected the necessary supplies, you’re ready to begin! 

  1. Fill the large container with about five gallons of water. Any temperature of the water will be fine.
  2. Access your water supply line by unhooking the water meter.
  3. Place the storage container filled with water under the opening of the pipe.
  4. If your supply line doesn’t already have a valve, attach the gate valve. 
  5. Using the pond pump, force water through the nylon hose.
  6. Place the hose into the supply line and move it through, allowing the water in the hose to melt the blockages. 
  7. Keep doing this until water is flowing freely. This shows there is no more ice blocking the supply line!
  8. Turn off the valve.
  9. Reconnect the meter.
  10. Turn the valve back on. 

Once the water meter is reconnected and the valve is back on, you should be good to go! This method can take several hours to complete, but it could save you the hassle and expense of hiring a professional plumber.

Hire a Professional

That being said, sometimes a professional is worth the expense. If all else fails, or if you simply don’t want to do it yourself, hiring a professional plumber is always an option. They may need to use more invasive methods to thaw the underground pipes, such as excavating the pipes. It sounds extreme, but this method would also allow them to add insulation around the pipes, hopefully preventing freezing from happening again in the future.


Speaking of prevention, this is the most effective way to be sure you won’t have to thaw frozen pipes underground! After dealing with this issue once, you probably won’t want to deal with it again. Several things can be done to prevent frozen underground pipes in the future. Some of these prevention methods will have to wait for spring (no one wants to dig into frozen soil), but some of them can be done right away!

Bury Your Pipes Below the Frost Line

If pipes are not buried deep enough in the ground, they might be more prone to freezing. A professional will need to assess the pipes and determine if they are buried deeply enough. If not, they can bury them deeper. Of course, this is something that will have to wait until winter is over because it’s very difficult to dig into the ground that’s frozen. While this is an expensive option, it could be worth it in the long run!


A special type of insulation is required for underground pipes. The regular insulation used in a house simply won’t do because it will break apart after it’s buried. This option can be quite effective, although also expensive. A professional is also necessary for the proper installation of the insulation.

Prepare for Winter

As winter approaches, there are several important steps to take to prevent frozen pipes underground. Some of these are steps you can take even with winter in full swing! Here’s what you can do:

  • Unhook your garden hose from the spout
  • Cover exterior faucets to reduce cold air exposure to the pipes
  • Blow out your sprinkler system
  • Drain the pipes completely if you plan to go on vacation or leave for an extended time
  • Turn on a faucet to keep water running when you’re expecting very cold temperatures (even a trickle can keep pipes from freezing)
  • Insulate any exposed pipes with a pipe sponge or something similar

How to Thaw Frozen Pipes Underground Summarized

Discovering your pipes are frozen can be stressful, particularly if they are underground. Whether you choose to solve the problem yourself or hire a professional, you can get your water flowing again! Just be sure to try some of the preventative steps so your winter mornings won’t be derailed again. At least, not by frozen pipes!

Written by: Heather Hayes

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