How to Locate a Leak In a Lawn Sprinkler System

Examine the area where the lawn-sprinkler system's pipes are located. Look for damp spots that don't dry out between watering sessions. Unless the area is particularly low and doesn't drain properly, that area may be a possible leak zone.

Locate where the sprinkler system hooks onto the house's water supply. This is often just outside the house, but it may be inside. Check all connections by feeling them with your hand. If the connections are wet, use a wrench to turn the connections 1/4 turn. Even if the leaky connection is inside, the water may be running along the pipe to the outside.

Follow the sprinkler's water line from the house to the valve box, which is often on the side of the house or in a flowerbed. Examine the water connections from the valve box. If you feel or see water drops or condensation around the valve box, tighten the connections using a wrench.

Straighten all of the sprinkler heads. If a head gets too far to one side or the other, it may appear to be leaking, but it's just not distributing water the way it should. If the ground is damp, simply pull the head into place with your hand. Tamp dirt around it to hold it firmly in place. If you can't move the sprinkler head by hand, loosen the dirt around it with a hand trowel, move the sprinkler head into position and replace the dirt.

Dig out irrigation pipes with a shovel as a last resort to find leaks. Start at the spot that's the wettest. Dig down to the pipe and any nearby joints. Feel the pipe and joints for leaks, as well as look at them. Work your way away from the wet zone. If there is a leak, unfasten the connections at the joint and remove them. Wipe pipe cement on the end of the pipe and refasten new connections into place.