Similar to PEX pipe, black poly pipe is made from polyethylene and known for durability.

However, like othertypes of plumbing pipes, it does not last forever.

Black poly pipe can develop leaks with time and with the help of tree roots.

Black poly pipe with leak being fixed below ground

The Spruce / Kevin Norris

As roots grow, they push against the pipe and eventually break it.

Sometimes you will be able to locate the problem by digging up the wet area in your yard.

Either way, expect to do a fair amount of digging.

Materials and tools to fix a leaking black poly pipe

The Spruce / Kevin Norris

The center will notify all utility companies with service lines on your property.

Black Poly Pipe Sizes and Fittings

Black poly pipe comes in a very wide variety of sizes.

It is good practice to double up on the clamp on each joint for extra strength at the connection.

Water pipe turned off by turning shutoff valve lever

The Spruce / Kevin Norris

Be sure to follow all local code requirements for the repair.

Check your local codes to ensure you’re using the proper tools and materials.

Shut the Water Off

You dont want to be bailing water while you are trying to dig.

Shovel digging carefully around black poly pipe underground

The Spruce / Kevin Norris

Or, turn the water on once the pipe is exposed to see exactly where the leak is located.

Otherwise, dig slowly.

As you get close to the right depth, switch to a smaller trenching-style shovel for more control.

Exposed black poly pipe being cute with blue pipe cutter to make repair

The Spruce / Kevin Norris

double-check to expose all the way around and under the pipe to make it easy for you to work.

Plan the Cut

First double-check the location of the leak.

Decide how best to cut the pipe to make the repair based on where it is located.

Black poly pipe inserted with barbed fitting and pipe clamps

The Spruce / Kevin Norris

Then use apipe cutterto cut the pipe.

Insert one end of the fitting into the pipe, pushing it in as far as it will go.

Tighten the Clamps

Slide the hose clamps up so they are positioned over the barbs.

Black poly pipe with hose clamps tightened with screwdriver

The Spruce / Kevin Norris

Tighten each of the hose clamps with a screwdriver, using the pinch clamp tool if necessary.

double-check the clamps are secure and dont move around.

Check for Leaks

Turn the water on to check for leaks before backfilling over the pipe.

Black poly pipe checked for leaks with clamps secured

The Spruce / Kevin Norris

Underground water linesare commonly made from polyethylene, PVC, and PEX.

PEX fittingscan be used on polyethylene when barbed insert fittings are used, sometimes requiring clamps.

PVC, brass, and steel fittings are the most popular choices for attaching black poly pipes together.

Study Confirms Long Life Expectancy for Polyethylene Pipe in Municipal Water Systems.