I HAVE HUNTER SPRINKLER HEADS. I NOTICED THIS SPRING THAT SEVERAL HEADS SEEM TO BE LEAKING FROM A TINY HOLE ON THE STEM WHERE THE SPRING IS LOCATED. WHAT CAUSES THE HOLE?
The hole is built in, as a means to drain away water that leaks by the rotor seals. Some heads will have a drip or dribble from there. If it didn't drain away, it could freeze over winter, destroying the head.
