The question is broad. There are many components that can cause your sprinkler system to fail. Here I will list the five top reasons causing your lawn sprinkler system repairs. Keep in mind this are not all the reasons, because they are so many. However, it does deliver the top five reasons I see daily over my thirty years of working on lawn sprinkler systems. If your system is down its probably for one of the top five reasons listed below.
1. Sprinkler Leaks
2. Pipe Leaks
3. Solenoid Malfunctioning
4. Malfunctioning or worn-out valve
5. Backflow Repairs