Most of the time, checking each sprinkler head for proper function and distribution will identify problems before the landscape starts suffering.

A major problem with most irrigation systems is poor distribution and maintenance. Use this checklist to identify and fix problems yourself or call a licensed irrigation specialist:

Sprinkler head spraying water onto the sidewalk, driveway, or road
Fix:  Redirect pop up nozzles so that water is applied only on the landscape.  If your spray pattern is greater than your landscaped area you may need to replace the nozzle with a different spray pattern.
Spray nozzle missing, not operating, or reduced water flow
Fix:  Replace nozzle and filter; check nozzle and filter for damage or blockage.
Poor distribution pattern
Fix:  Check nozzle for damage or blockage; replace nozzle with proper pattern; increase or decrease throw by turning screw on top of nozzle. Tighten the screw to decrease the throw or loosen the screw to lengthen the throw.
Sprinkler head bubbling or gushing water out the top
Fix:  Cracked or broken nozzle; replace nozzle.
Sprinkler head no longer straight up and down
Fix:  Reset pipe to perpendicular; this may require you to loosen the soil around the irrigation head and riser, pull the head perpendicular and then tamp the soil back in place or re-install the tee.
Sprinkler creates a cloud of mist
Fix:  Usually caused by too much pressure; install pressure regulator either at meter or use pressure regulating heads.
Grass, shrubbery or tree blocking distribution pattern
Fix:  Raise or lower riser; move sprinkler head.
Dry landscape areas or poor coverage
Fix:  Correct distribution; maintain a mulch layer on all planted beds; aerate and add about ½ inch of compost to lawn area.
Water bubbling, dripping or gushing all the time
Fix:  Broken or leaking pipe or valve.
Runoff occurs before adequate water is applied
Fix:  Soak and cycle – on your irrigation controller set the station to run for two or three short intervals instead of one longer time.
Area along road, driveway or sidewalk stays too dry
Fix:  Correct poor distribution; run this station for several short periods with about 30 minutes in between cycles; aerate and add about ½ inch of compost. The best alternative for this area may be to hand water or utilize soaker hoses.