SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

So a few months back I lost pressure in one zone. Called my normal contractor (company A) and he said the well probably cavitated and I’ll need a new one. ANNNNNNDD, I got a second opinion. Different company (company B) put new (low pressure/output) heads on the entire zone. Well it still doesn’t work (it’s a long story and I won’t be calling them back). 3 zones work fine, aside from being a little slow to pressurize. Well I noticed this giant crack in the pipe leading from the index valve. Why no one noticed this is beyond me. Anyway, I fixed it and it still has no pressure. What are the potential causes?

Other broken pipes?
Cavitated well?
Bad index valve?

Others?

Quoted from "Wet_Boots"

Try to evaluate the well on its own, just as a water source, and not what drives a sprinkler system. If you have to add some shut-off valves and outlet tees, consider it the cost of being able to know what you have, instead of having to guess at it.

This advice comes from the word "cavitated" that you posted, which suggests that the water source may have changed in some way. Water tables can drop lower, to a point where it is beyond the ability of a pump to bring water to the surface, at least in the same quantity and pressure as was done originally. Another change that affects pump output is a well point screen becoming clogged, with similar effects on pump output.

All of the other zones work fine though. And we’d had plenty of rain, so the water table is currently high. Even years back when we had a drought they all worked. Does that make a difference?

Also, I have an in-line spigot which flows plenty of water.