In TX, the locator will not mark private lines.
So, it this part of the country you would have done nothing wrong. Yeh, get it fixed but have the plumber bill the homeowner. You might split the costs.
We've put it in our u/g work contracts that we're not responsible for lines that are not located. If it's under 30' long we dig it by hand due to all the sprinkler lines.
Rigid does not hold up well to the effects of chlorine gas from the pool. It's much better than EMT but not as good as PVC. Anything below 3' and 10' horizontally from the pool is corroded in about 5 years(especially aluminum bell boxes).