I am going to install a submersible pump in a spring catchment cistern about 200 to 220 feet below the holding cistern right outside the house. The overall run is 1300 feet but the elevation difference is about 200 to 220 feet.

I am running 1" 200 PSI Black PE water pipe. Gould's pump techs state that you should install a check valve every 200 feet of elevation rise. They could not tell me why though. LOL. Can anyone here tell me why this may be the case? Do I need to install a checkvalve somewhere in that 1300 foot run? I would be right 'on the edge' in terms of whether it is necessary or not.

Thanks,
Scott