PEX piping has revolutionized plumbing systems due to its flexibility,
durability, and cost-effectiveness. A common question among homeowners and
contractors is: "Can I bury PEX pipe?" The short answer is yes, but proper
installation practices are critical for long-term performance. This article
explores how to bury PEX pipe safely, key considerations for underground
use.
Understanding PEX Pipe and Underground Use
PEX is resistant to corrosion, freezing (to a degree), and chemical damage,
making it suitable for buried applications. However, its performance depends on
correct installation. Let’s break down the essentials:
1. Is PEX Pipe Rated for Direct Burial?
Most PEX tubing (e.g., PEX-A, PEX-B) is approved for direct burial, but
check local building codes first. Some regions mandate specific burial depths or
require protective sleeving in high-risk areas (e.g., rocky soil).
2. Key Factors for Burying PEX Pipe
Depth Requirements: Bury PEX at least 12–18 inches deep to prevent freezing
or accidental damage. Deeper burial (24+ inches) may be needed in colder
climates.
Soil Conditions: Avoid sharp rocks or debris that could puncture the pipe.
Use sand as a bedding material for added protection.
UV Exposure: PEX degrades in sunlight. Ensure buried sections are fully
covered; above-ground portions must be UV-resistant or shielded.
How to Bury PEX Pipe: Step-by-Step Guide
Follow these steps to ensure a durable underground PEX installation:
Step 1: Check Local Codes
Verify burial depth, sleeve requirements, and permit rules with your
municipal authority.
Step 2: Choose the Right PEX Type
Use PEX tubing rated for potable water (marked with NSF/ANSI 61
certification).
Opt for color-coded pipes (red for hot, blue for cold) to simplify future
repairs.
Step 3: Dig the Trench
Excavate a trench at the required depth.
Line the trench with 2–3 inches of sand to cushion the pipe.
Step 4: Install the Pipe
Lay the PEX in gentle curves—avoid kinks.
Use protective sleeving (e.g., PVC) if crossing under driveways or
high-traffic areas.
Step 5: Backfill Carefully
Cover the pipe with sand before adding soil to prevent sharp objects from
damaging it.
Leave a warning tape 6–12 inches above the pipe to alert future
excavators.
Common Mistakes to Avoid
Shallow Burial: Insufficient depth increases freeze risk.
Ignoring Sleeving: Failing to protect pipes under concrete slabs or rocky
soil leads to leaks.
Poor Joint Placement: Keep fittings accessible (e.g., in valve boxes) for
easy maintenance.
Benefits of Burying PEX Pipe
1.Freeze Resistance: PEX can expand slightly, reducing burst risk compared
to rigid pipes.
2.Corrosion Proof: Unlike metal pipes, PEX won’t rust or corrode.
3.Cost-Effective: Lower material and labor costs vs. copper or PVC.
FAQs About Burying PEX Pipe
Q: How long does buried PEX last?
A: Properly installed PEX can last 40–50 years underground.
Q: Can rodents chew through buried PEX?
A: While rare, rodents may damage pipes. Use metal sleeving in high-risk
areas.
Q: Does PEX leach chemicals into soil?
A: NSF-certified PEX is safe for drinking water and won’t contaminate
soil.
