I quoted a residential property for an irrigation system w/ a well. I have not measured the actual pressure and flow yet... but she thinks it is 6gpm. I am guessing 1/2".... maybe 3/4" supply line. I am going to check flow, pressure and the main a week before the project, but want to what your opinions are. I have estimated only 4 rotors per zone... and w/ PGP nozzles 1 or 2... I would have less than 1 GPM per head. I have always installed systems w/ at least 20gpms and good pressure, so I would like advise from anybody that has experience w/ wells.