To insulate your water pipes underground, you need to cover them in insulation materials and then waterproof the insulation before you can backfill the area.
Your water pipes are buried underground to protect these pipes from the natural elements and to keep them out of sight and out of the way.
However, if you want to make your underground water pipes as energy-efficient as possible and prevent sweating or freezing, you can insulate and waterproof these pipes yourself.
Why are water pipes buried?
Your water pipes may be buried for a range of reasons, but the most common reason is that burying water pipes deep underground keeps the pipes secure and out of harm’s way.
When pipes are buried, the water flowing through them is not as exposed to the elements, and they are also not a tripping hazard around your home.
This means that the purpose of burying pipes is two-fold, it protects the pipes, and it also helps your home look nicer and so that your yard can be safer.
How to insulate water pipes underground
In order to get the most out of your underground water pipes, you need to ensure that your pipes are well-insulated. Insulating underground water pipes will prevent sweating in the hotter, summer months and it will also prevent freezing in the winter months.
Well-insulated water pipes also prevent any unnecessary heat loss, which will make your water heating system function more efficiently and effectively.
However, knowing that your underground pipes need to be insulated and knowing how to insulate these pipes are two different matters. In order to insulate your water pipes underground, you need to use speciality insulation materials around the pipe.
Then, you will need to make sure that this insulation is water-proofed, as groundwater and other elements can damage your insulation and pipes over time.
This will ultimately mean that you have done all the work to insulate these underground pipes, only for this work to be undone in a few months because the insulation has been destroyed by the elements.
When this insulation process has been completed, you need to backfill the area that you dug around your pipes to make sure that these pipes stay secure and safe.
During this backfill process, you will be able to add even more insulation to your pipes by choosing the materials you use wisely and carefully.
After you have completed this insulating process, your pipes should be protected from corrosion, tree roots, and harsh weather conditions and should end up lasting for a longer time.
How to add insulation to underground water pipes
Some homeowners use the regular insulation that you would use for your home, like this Reflective Foam Insulation for their outdoor pipes.
 |
| Buy it on Amazon |
However, there are much more convenient, speciality water pipe insulation materials available, such as:
| Speciality insulation | Description | Price | Available on Amazon |
| Foam pipe covers | These covers are pre-slit and self-sealing, which makes them quite easy to install as they simply slip over the pipes | $19.94 for 43-feet sticks |  |
| Buy it on Amazon | |||
| Pipe wrap insulation | This product wraps around your pipe and prevents heat loss and sweating | $8.40 for 25 feet |  |
| Buy it on Amazon | |||
| Pipe heating cable | This cable is plugged in and strapped to your water pipes to self-regulate the temperature and warm up the pipes | $139.99 for 120 feet |  |
| Buy it on Amazon |
These items go over (by surrounding) or right next to your underground water pipes to protect them from harsh weather conditions.
How to waterproof your underground water pipe insulation
After you have insulated your underground water pipes, you can extend the life and effectiveness of this insulation and your pipes by ensuring that the insulation is waterproof.
The simplest way to do this is to wrap a plastic tarp around the insulation, which is around the pipes like a blanket. You can then secure this plastic tarp with tape or zip-ties to keep it in place underground.
You can also purchase PVC pipe to fit over the pipes and their insulation. In this case, it is important that you ensure that the pipe is white and not black, as the black pipes are not completely waterproof and this can cause corrosion and inefficiency when it comes to the purpose of insulation.
 |
 |
 |
 |
| Buy it on Amazon | Buy it on Amazon | Buy it on Amazon | Buy it on Amazon |
How to backfill the area for improved insulation
Once your underground water pipes have been insulated and the insulation has been made waterproof, you need to fill the holes you dug to get the pipes back up.
However, if you choose to fill these holes with sand, like this Play sand, which is available for $39.99 per 20 pound bag, you can add even more insulation around the pipes, as opposed to just filling the holes back up with dirt.