Sprinkler heads in built-in sprinkler systems are susceptible to damage from lawnmowers, debris and bad weather conditions. To replace broken or cracked sprinklers:
Replace sprinkler heads with the same type of head. The manufacturer and model number are usually printed on the top of the head.
To dig out the old head, dig a hole around one foot away from the head in all directions. Dig down to the pipe connected to the head. Be careful while digging, as it is easy to cut through a pipe.
Unscrew the old head from the pipe by turning the head in a counterclockwise motion. If the head is stuck, use a wrench or pliers to gently pry it loose. Do not get dirt in the pipe.
Screw the new head into the pipe.
Replace the dirt and grass around the sprinkler head. Make sure it fits tightly on the pipe.
Screw the nozzle onto the sprinkler head stem.