We recently installed a 3 zone 13 head system. We are using well water with a 1 HP pump. The pressure gauge reads 45 PSI. After turning on a zone the water starts out real strong and after 30 seconds it dies down to trickle. Don't know if its the pump or the pressure tank. This is a 1" line running from the pump to the system. There is also 3/4 " copper line running to a outside faucet which works fine. Thanks, Marty