Leaking Outdoor Sprinkler Line

Causes of Leaks

• When underground sprinkler lines freeze, the water inside expands. With nowhere to go, the water presses against the edges of the pipe. This can cause the pipe to crack or burst. Underground pipes are also held together with chemical cement on PVC pipe or clamps on poly pipes. If the glue becomes corroded or the clamps lose their grip over time, the connection points can become loose and no longer waterproof. When this happens, water can burst from the seams at pipe connection points.

Finding Leaks

• Figuring out exactly where your pipe is leaking can be a challenge. One of the best techniques for identifying a leak is to plug the sprinkler heads with PVC caps before running the system for an hour or so. The area near the leak will begin to pool with water. This will give you a rough idea of where to dig up the line, but it could save you a lot of work trying to find a crack underground.

Repairing Leaks

• Sprinkler pipes are rigid, so it's possible to fix them with two techniques. One method involves placing a clamp with a rubber gasket around the area of the leak. When you tighten the bolts on the clamp, the gasket will press against the crack and seal in the water. This is especially useful for PVC pipes. Some pipes that are connected with PVC cement will have to be disassembled and re-glued for the best performance.

Other Leak Points

• Sprinkler systems can also leak at the point where the supply line meets the sprinkler risers. Risers are generally made out of PVC and are attached to the pipe with a T-fitting. This fitting requires glue or clamps to connect to the main line. You can spot a leaking riser by the pooling of water near the base of the sprinkler. Once you've identified the troublesome sprinkler, you will have to disassemble and replace the T-fitting to ensure a water-tight connection.