What is the best pipe to use for underground water line?

Author: Oliver Bahringer  |  Last update: Wednesday, June 4, 2025

High-density polyethylene (HDPE) pipe is a good choice for underground water lines because of how the pipe is connected. Rather than using joints, which can leak, or glues and cement, which can degrade over time, HDPE pipe is connected via plastic fusion.

Is PEX or PVC better for underground water lines?

Comparison between PEX pipes and PVC pipes for water supply systems. 1. Durability: Both PEX pipes and PVC pipes are known for their durability and long-lasting nature. However, PEX pipes tend to have better resistance to extreme temperatures and thermal expansion/contraction, making them less prone to leaks or bursts.

Is PEX better than PVC for burial?

Pex is the better material. Rodents can chew holes in either but more easily with pex. Neither has good uv resistance and pex can absolutely not be in direct sunlight. Pvc is cheaper but pex is the easiest thing to work with. But if rodents are an issue then copper is really the way to go.

What type of pipe is not recommended for a water line?

PVC is most commonly used for drain, waste, and vent lines. It is not recommended for use in potable water lines because it can leach chemicals into the water.

What is the longest lasting underground pipe?

Cast iron will last anywhere from 75-100 years while PVC wins the award for longest-lasting pipe material with an indefinite lifespan.

How to Choose Water Supply Piping | This Old House

Which pipe is not recommended to be buried underground?

Cast Iron

Despite the heat resistance and noise-dampening properties of cast iron, it's not as suitable for underground water supply as newer materials. Cast iron is not resistant to corrosion, which can compromise the quality of the water supply and damage the integrity of the piping, leading to leaks and breaks.

What is the best quality pipe for underground water supply?

HDPE offers flexibility because it can withstand strong impacts. Be it the weather condition or the force of water, these pipes serve uniformly during every situation. So, when you install these pipes for underground water supply, you can trust the quality. Moreover, these pipes remain unaffected due to motion fatigue.

What is the best material for underground water pipes?

PVC (polyvinyl chloride) is a durable plastic pipe that is highly resistant to corrosion and impact damage. The material doesn't melt easily, which works well for underground water lines. PVC pipes also come in different diameters, so it is easy to find the right size for both residential and commercial applications.

What pipes to avoid?

Polybutylene, Galvanized Steel, and Lead Piping: The Worst Plumbing Pipe Materials.

What is the best pipe for an outdoor water line?

High-Density Polyethylene (HDPE, often just "PE") has become one of the most popular choices for underground service lines, thanks to its corrosion-resistance, durability, and competitive price. Some codes require that buried plastic lines under 2" in diameter be PE (rather than PVC).

Is PEX ok to run underground?

Yes, PEX pipes can be buried underground. However, it's important to follow local building codes and guidelines to ensure compliance and the longevity of your plumbing system. To ensure optimal performance and protection against external factors, it is essential to bury insulated PEX pipe at the appropriate depth.

What is the most expensive water pipe material to install?

Cost Comparison

Galvanized steel pipes tend to be the most expensive option and can be costly to install and repair. Copper can be a costly material, but it may still be a good choice if you value durability and reliability.

What is a black water pipe called?

Black poly pipe (polyethylene or PE pipe) is used in many facets of home plumbing, both for drinking water lines and other applications inside a residential house. This type of pipe is available in very long rolls for the water main between the meter and the house and for sprinkler systems.

Why do plumbers not use PEX?

Material Concerns: One of the primary concerns about Pex plumbing is the material itself. While Pex pipes are undoubtedly flexible, making them easier to install in tight spaces, they are not as durable as traditional materials like copper or even PVC.

How long will PEX water lines last underground?

On average, PEX pipes can last anywhere from 40 to 50 years, and in some cases, even longer.

What is the healthiest water pipe?

Healthier Plumbing
  • Copper or polypropylene pipes.
  • “Lead-free” joint materials, with less than 0.20 percent lead.
  • “Lead-free” faucets and fixtures, with less than 0.25 percent lead.

What is the bad type of plumbing pipe?

Today, copper and PEX are considered the best types of pipes for residential plumbing, and your insurance provider will love you for having them. On the other hand, PVC is less favored while Galvanized is considered one of the worst types.

What kind of pipes do plumbers use?

Copper and PEX are the most common pipe materials used in homes. Copper pipes are durable, corrosion-resistant, and can be used for hot and cold water. PEX seems to be replacing copper pipes at a high rate since it is less expensive, more flexible, and easier to install.

What type of pipes last the longest?

PVC can last even longer than steel or copper, which are some of the most durable metals for plumbing pipes. Ability to handle pressure: PVC can withstand high water pressure, which makes it an excellent choice for the main supply line in your home.

How deep to bury a water line?

Code Requirements for Water Lines

The standard depth for water lines in the U.S. is around 36 inches, but this can vary from location to location.

What is the difference between type A and type B PEX pipe?

PEX A offers higher burst resistance, capable of withstanding up to 500 PSI in extreme cold, while PEX B, being more rigid, is less resilient.

Which PVC pipe is best for underground water supply?

PVC pipe schedules can range from 10 to 160 but schedules 40, 80, and 120 are the most commonly used for underground applications. The higher the schedule, the thicker the pipe wall. Different-schedule pipes may have the same exterior diameter but have distinct interior diameters.

What is the best material for underground water line?

PVC and HDPE remain popular choices for their versatility and cost-effectiveness, while ductile iron and copper offer longevity and reliability, especially for main water lines.

Can PEX be buried?

Can you bury PEX? Yes, you can bury SharkBite PEX-a and PEX-b pipe in most applications, as it's approved to AWWA C904, which covers PEX pipe in regard to burial. Be sure to check with local, city or state codes to see if the pipe needs to have sleeves or any type of protective burial for your area.

What size pipe is used for underground water lines?

For this reason, Type K pipes are often used underground, for industrial use, or in commercial buildings. The wall thickness of a Type K pipe varies between 0.035 inches to 0.271 inches, depending on the nominal pipe size (NPS).

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