What is the most common cause of sprinkler system failure?

Most common cause of sprinkler system failure is clogged or damaged sprinkler heads and valves, caused by dirt, sand, grass clippings, and lawn mower damage, leading to uneven watering or zones not working. Other common causes include broken sprinkler heads from mowers and foot traffic that cause leaks and low pressure, electrical failures like faulty solenoid, timer, controller, or wiring that prevent valves from opening, and leaks in underground pipes from freezing, root intrusion, or shifting soil. Clogged nozzles from hard water deposits reduce flow. Low water pressure from too many heads on one zone or leaks causes weak spray. Failed backflow preventer prevents system operation. Controller programming errors cause system not to run at correct times. Seasonal issues like frozen pipes in winter if not winterized cause burst pipes. Overall, physical damage to heads and clogging from debris is most common, followed by electrical issues with valves and controller, accounting for majority of service calls for irrigation repair.