Underground water pipes are an essential part of any home. They transport water when and where it’s needed and frankly, many homeowners take this process for granted. Until something goes wrong.

If you live in a part of the country where freezing temperatures occur, insulating underground water pipes is an essential part of keeping the water flowing when you and your family need it. In addition, insulation also helps to prevent condensation, corrosion, vapor leaks and it helps to regulate the temperature of the water flowing through those pipes.

Underground, moisture and corrosion are a constant threat to your pipes. Even with resistant coatings, the constant exposure to water and chemicals in the soil can easily create problems. Insulating the pipes helps to provide an additional measure of protection for them.

The bottom line is that insulating underground water pipes will help to lengthen the lifespan of your water pipes.

What Is The Best Insulation For Underground Water Pipes?

Inserting your water pipes inside a larger pipe that is insulated is the most watertight system for underground pipes.

Step #1 – Minimum of 30 inch Trench

The water pipe should be placed in a trench that is at least 30 inches deep. Depending on where you live, you will want to dig a trench that is below the frost line which can sometimes be as little as 18 inches or as much as 4 feet.

Step #2 – Gravel and Heavy Plastic Wrap

Place about 3 inches of gravel in the trench and then a large heavy plastic wrap. Make sure it’s large enough to eventually wrap around the large pipes that you will be using.

Step #3 – Large Pipes

The large pipes that you will be inserting your smaller water pipes in need to be large enough to not only accommodate the water pipe but also to accommodate insulation that you will be stuffing into it to help protect the water pipe.

Step #4 – Foam Board Insulation

Add strips of the foam board insulation or polystrene into the large pipe and push the water pipe through it. By now the large pipes with the smaller water pipes and insulation should be sitting in the trench on top of the gravel and plastic sheeting.

Step #5 – Wrap The Pipes

Fold the plastic sheeting around the insulation and the water pipes. Go ahead and tape the edges of the plastic sheet to help keep it in place and insulated.

Step #6 – Add Top Soil

Now that everything is in place, go ahead and fill the trench with soil.

Is It Worth Insulating Water Pipes?

Your underground pipes are exposed not only to freezing temperatures if you live in areas with cold weather, but they can also be exposed to corrosion and damage from tree roots as well as human error (i.e. cable installations, etc.)

Insulating your water pipes not only saves you a little bit of money on your hot water bill but it can extend the lifespan of your pipes. Overall, if you are planning to live in your home for 7 years or more, insulating your underground water pipes will save you money.


Insulation is important for underground water pipes because it protects them from the cold, from corrosion and other elements.. If you live in an area that experiences extreme winter weather, then insulation may be necessary to protect your pipes and prevent freezing or bursting. These are some of the many reasons why it’s important to insulate your underground water pipe system. It will help keep temperatures regulated, which can save time on costly repairs during emergency situations!

If you have any questions about underground pipes or are having some problems with it, call Atlantis Plumbing today at 770-443-8229. We are available 24 hours a day, 7 days a week.