Can You Bury PEX? Things You Need To Know About PEX

Piping is an important component of any building project. It serves as a conduit for various water and electrical connections in a structure. Many different piping materials are best suited to a specific use. The most popular types of pipes are copper, PVC, and PEX.

PEX tubing is a flexible, noncorrosive polymer tubing mostly used for water supply in homes. It can be useful for other purposes. So, is it possible to bury PEX pipes in the same way you bury metal or PVC pipes underground? Let’s respond to the question.

Can You Bury PEX?

Yes, you can bury PEX. PEX piping is a common choice for direct subsurface burial due to its expansion ability. As a result, there’s less chance of hard pipe freezing. However, water can freeze in PEX in cold weather, weakening the pipe, blowing connections or fittings, or creating leaks or burst pipes.

It’s best to bury PEX tubing below the frost level to keep it from freezing. To determine the necessary depth, contact your local or municipal water company. When running PEX pipes underground, use sand to protect the pipes from damage by rocks and stone chips.

Alternatively, you can run the PEX through PVC piping, which functions as a sheath to protect the tubing from damage and freezing. 

Is Burying PEX Pipe Underground Up To Code?

PEX piping complies with all major construction codes, including cold and hot water distribution, radiant floor heating, and water service lines. To verify that you comply, check to see what codes (local, state, and federal) apply to you.

About PEX

Cross-linked (PEX) is a common plastic piping with improved heat resistance, strength, and stability. It’s useful in service lines, hot and cold water distribution systems, residential fire sprinkler systems, hydronic heating applications, and cable insulation.

It is also utilized for natural gas and offshore oil transportation, chemical transfer, and sewage and slurry conveyance. In addition, PEX is a better and cheaper alternative to PVC, CPVC, and copper tubing for household water pipes.

PEX Piping Types

There are three types of PEX piping: 

Type A PEX piping is the most adaptable, useful for all residential water demands, including potable water plumbing. Because Type A PEX piping expands most of the three types, it is the least susceptible to freezing and breaking. While type A PEX piping is more expensive than the other two varieties, it is less expensive than copper plumbing.

Type B PEX piping is stiffer and has a strong coil memory,making installation more challenging. Like Type A, it expands in cold conditions, preventing cracking. 

However, it’s less expensive than Type A and is more resistant to chlorine in water sources, which means it will not break down in locations where the drinking water has a high amount of chlorine.

The stiffest of the three, Type C PEX piping, is more susceptible to kinking and cracking than the other two. It’s frequently utilized for minor repairs that don’t require ending. PEX piping of type C is typically less expensive than the other two varieties.

PEX Pipe Advantages

There are many benefits of PEX piping, including:

Lower installation costs: PEX is around a third the price of copper piping. And if you’re building a new house, the savings might be substantial. Also, copper’s price swings between markets, whereas PEX’s is less volatile.

Resistant to corrosion: PEX resists corrosion, mineral accumulation, and erosion better than galvanized steel and copper.

Easy to install: PEX’s flexibility makes it simple to install in difficult-to-reach locations.You don’t need a plumbing license to install PEX pipe for many modest DIY tasks.

They are more efficient: PEX pipes are smaller in diameter than traditional pipes; they provide hot water faster and waste less water. Also, PEX has better thermal conductivity than conventional pipes, reducing heat loss.

Noiseless: PEX pipes are synthetic plastic, producing little or no noise.

PEX Pipe Disadvantages

PEX piping has some drawbacks, which are:

Installation challenge: Some people may find it easy to install PEX pipes, while others may struggle with it. We advise using professionals to install pipes, especially if moving elements, lines from adjacent rooms, or new construction.

Not heat-resistant: PEX is prone to failure in high-heat environments, so don’t connect it directly to water heaters.

UV light sensitivity: Because PEX is highly susceptible to UV light, it is important to keep all PEX pipes out of direct sunlight and UV lightbulbs. Numerous manufacturers advocate complete darkness for PEX pipes, which restricts the locations where you can install them.

Chemical issues: There have been reports of leaching hazardous substances such as BPA and other pollutants from PEX pipes. Excess chlorine in water can also damage PEX.

Permeability. Because PEX is a plastic material, there is a risk of damage, and rodents can even nibble through the pipes. PEX is not intended for outdoor use or exposure to the environment. PEX is permeable, which implies that liquids can pass through it.

How Deep To Bury PEX Water Line?

If you want to avoid freezing, all underground piping should be buried 12-18″ below the frost line, which is the depth at which subsurface groundwater freezes. It can be three to four feet deep in colder zones. Check out the US Department of Commerce’s data or this map of US frost lines. 0″ – 100″ underground

Do PEX Pipes Burst Or Freeze?

Because PEX tubing is flexible, it expands when water freezes inside it. Water thawing returns the tube to its natural shape. This property makes PEX pipe freeze-proof. But it doesn’t mean it’s freeze-proof. Water in pipes freezes at temperatures below 20°F.

The high-pressure potential of PEX reduces the possibility of pipe burst due to ice formation. Ice in hard lines increases the risk of pipe breakage or exploding. 

Remember that frequent expansion and contraction can weaken the tubing, causing leaks or pipe failure. Also, when water freezes in the lines, flaws in the tubing might cause rupture.

PEX Connectors And Fittings

PEX connections and fittings exist in a wide range of shapes and sizes. Therefore, a specialist tool is necessary for some connecting methods. The bulk of these connection fittings and equipment are available in big box stores and the internet.

Manufacturers use various connecting methods, but they generally fall into five categories. 

Crimp fittings:

The most common form of fitting in PEX systems is crimp fitting. PEX-to-PEX connections and transitions to other pipe materials are possible using a wide range of fittings.While most crimp fittings are brass, poly-alloy crimp fittings are also available.

Compression fittings:

Compression fittings are popular among plumbers, contractors, and DIY homeowners due to their ease of installation and disassembly. Crimp fittings, on the other hand, are less expensive. Compression fittings are good when several connection sites or disassembly are expected.

Push-Fit fittings:

These are a relatively new plumbing innovation that is quickly gaining favor for all types of plumbing pipes, including PEX. No special equipment or crimp rings are needed to connect PEX tubing with push-fit fittings.

Using a sophisticated multicomponent locking mechanism, you can put the PEX pipe into the fitting. Then, using a special disconnecting tool, you can remove the fitting using the same technique.

All types of PEX tubing and copper and CPVC pipes are compatible with push-fit fittings made of brass or DZR brass.

Expansion fittings:

Expansion fittings are made of plastic and have a sleeve that fits the PEX tubing. Releasing the tool returns the sleeve to its original size. Then, the tubing and sleeve are quickly stretched and inflated to allow for the insertion of a fitting. Two proprietary systems use this type:

1. The ProPEX system by Uponor, which includes expansion fittings, PEX sleeves, and a unique expander tool ASTM F1960 standards, are followed in the production of the components.
2. The RauPEX system from Rehau comes with proprietary expansion fittings, an expander tool, a compression tool, and brass sleeves. ASTM F2080 standards are followed in the production of these fittings.

Only PEX-A tubing can be used with expansion-style fittings; other varieties of PEX tubing are not compatible.

Press fittings: Similar to crimp fittings, press fittings are built without an external crimp ring. Instead, when the PEX pipe is placed over the press-fitting sleeve, it is squeezed until it latches to the inserted sleeve with a press tool.

Press fittings are available for both PEX tubing and PEX-AL-PEX tubing. The systems are manufacturer-specific and must be used with the manufacturer’s press tool.

PEX Connections Tips

• Install PEX tubing whenever possible to reduce the number of fittings needed, reducing the risk of leaks and disruptions.
• Instead of making right-angle bends with fittings, bend the tubing to change directions whenever possible.
• To feed several PEX lines from a single supply pipe, use manifolds.
• When at all possible, group plumbing fixtures together.
• When planning your layout, keep tubing lengths to a minimum.
• Select the appropriate PEX pipe diameter for the job.
• Color coding with PEX is a good idea. The typical practice is blue for cold water lines and red for hot water lines.
• Bundle pipe runs together to save installation time.

Conclusion

PEX tubing is a flexible, noncorrosive polymer tubing mostly used in the home for water supply. PEX pipes, like metal and PVC pipes, can be buried underground.

Because of its capacity to expand, PEX pipe is a popular choice for direct subsurface burial. As a result, the risk of hard pipe freezing is reduced.

Bury PEX tubing below the frost line to avoid freezing. Use sand to shield PEX pipes from rocks and stone chips when running them underground.