PVC Pipe Underground: Everything You Need to Know Before You Bury

PVC (polyvinyl chloride) pipes are widely used in various plumbing and drainage applications. Their durability, affordability, and ease of installation make them a popular choice for both residential and commercial projects. However, one common question that arises is whether PVC pipes can be safely buried underground. This blog post provides a comprehensive guide to help you understand the factors to consider and the steps involved in burying PVC pipe in the ground.

Is It Safe to Bury PVC Pipe Underground?

Yes, it is generally safe to bury PVC pipe underground. However, certain precautions and considerations must be taken to ensure the pipe’s longevity and performance.

Factors to Consider Before Burying PVC Pipe

Soil Conditions

The type of soil in which you plan to bury the pipe can impact its durability. PVC pipes are not recommended for use in highly acidic or alkaline soils, as these can degrade the material over time.

Depth of Burial

The depth at which the pipe is buried is crucial. PVC pipes should be buried deep enough to avoid damage from surface loads, such as vehicles or heavy machinery. The minimum recommended burial depth varies depending on the pipe size and soil conditions.

Pipe Size and Pressure Rating

The size and pressure rating of the PVC pipe should be carefully considered. Larger pipes require greater burial depths, and pipes with higher pressure ratings are more resistant to external forces.

Steps for Burying PVC Pipe Underground

1. Prepare the Trench

Dig a trench deep enough to accommodate the required burial depth. The trench should be wide enough to allow for adequate bedding and backfill material around the pipe.

2. Install a Gravel Base

Lay a layer of crushed gravel at the bottom of the trench. This base provides support and drainage for the pipe.

3. Place the PVC Pipe

Carefully place the PVC pipe in the trench, ensuring that it is level and free of any kinks or bends.

4. Bed and Backfill

Surround the pipe with bedding material, such as sand or fine gravel. This material helps to support the pipe and prevent it from shifting. Backfill the trench with native soil, compacting it around the pipe to provide stability.

5. Protect from Surface Loads

If the pipe will be installed in an area that may experience surface loads, such as a driveway or parking lot, consider using a protective conduit or sleeve to shield the pipe from damage.

Types of PVC Pipe for Underground Use

Schedule 40 PVC

This is the most common type of PVC pipe used for underground applications. It offers a good balance of strength and flexibility.

Schedule 80 PVC

This type of PVC pipe has a thicker wall than Schedule 40 and is more resistant to high pressure and external forces.

SDR (Standard Dimension Ratio) PVC

SDR PVC pipes are designed with a specific ratio of pipe diameter to wall thickness. They are available in various SDR ratings, with lower SDR numbers indicating thicker walls.

Considerations for Burying PVC Pipe in Cold Climates

In areas with cold winters, additional precautions must be taken to prevent the PVC pipe from freezing and bursting.

Insulation

Insulating the PVC pipe with foam or other insulating materials can help prevent freezing.

Burial Depth

Bury the pipe deeper than the frost line in your area. This depth varies depending on the climate zone.

Slope the Pipe

Slope the pipe away from the water source to allow for drainage and prevent freezing water from accumulating in the pipe.

Can You Bury PVC Pipe in a Conduit?

Yes, burying PVC pipe in a conduit or sleeve can provide additional protection against external forces and surface loads. Conduits can be made of various materials, such as PVC, HDPE (high-density polyethylene), or corrugated metal.

Can You Bury PVC Pipe Under a Concrete Slab?

Yes, you can bury PVC pipe under a concrete slab. However, it is important to take precautions to prevent damage to the pipe from the weight of the concrete. Use a protective conduit or sleeve and bury the pipe deep enough to avoid direct contact with the concrete.

Can You Bury PVC Pipe for Drainage?

Yes, PVC pipes can be used for underground drainage applications. Schedule 40 or SDR PVC pipes are commonly used for this purpose. Ensure that the pipe is properly sloped to allow for water flow and that it is protected from potential blockages.

Can You Bury PVC Pipe for Electrical Wiring?

No, PVC pipes are not suitable for burying electrical wiring. Electrical wiring requires specialized conduits designed to protect the wires from moisture and electrical hazards.

Top Questions Asked

1. What is the minimum burial depth for PVC pipe?

The minimum burial depth depends on the pipe size and soil conditions. Generally, a minimum of 12 inches is recommended.

2. Can I use PVC pipe for underground irrigation?

Yes, PVC pipes are commonly used for underground irrigation systems. However, ensure that the pipe is rated for the specific pressure and temperature requirements of the irrigation system.

3. How do I prevent PVC pipe from freezing underground?

Insulate the pipe, bury it below the frost line, and slope it away from the water source to prevent freezing.

4. Can I bury PVC pipe in a yard with trees?

Yes, you can bury PVC pipe in a yard with trees. However, be aware that tree roots can potentially damage the pipe over time. Consider using a protective conduit or sleeve to shield the pipe from root intrusion.

5. Can I bury PVC pipe for sewer lines?

Yes, PVC pipes are suitable for underground sewer lines. However, consult with local building codes and regulations for specific requirements regarding sewer line installations.