South of 44 it's wise to install an irrigation filter to minimize clogging of the sprinkler heads.
I'm flushing my filter weekly due to collecting large amounts of sediment and algae with the low retention pond levels.
My irrigation guy said he is replacing far more heads than normal and thinks they may have reduced/stopped filtering and treating irrigation water as a cost savings (unconfirmed...)
Previous thread on irrigation filters.
Time to consider installing an Irrigation Filter?