Well

Hello,
I had a 200 foot well drilled. 1.5 hp pump 20 gpm. Well driller ran sched 80 1 inch up and out well. We tested the output after the pressure tank at about 30 gpm. it also has a csv installed before the tank. Heres my questions i'm running 300 foot of pvc pipe to a new 9000 foot building 6 bathrooms semi commercial kitchen. Is 1.5 inch pipe big enough. Well driller said 1 1/4 but does not seem big enough. Next question coming of the 300 foot main line i was going to tee off to my garage 100 foot on the way to building has 1 small bathroom, will rarely be used. Or should i tee off at the pressure tank run separate line to garage. Does it matter? I just want to have adequate pressure and volume. Im a journeyman plumber have done many residential homes just nothing this big and off a well.

Jay

The line to the garage has to be teed in after the CSV. If you put the CSV at the well head, your tank can still be in the house, but then you could tee into that line anywhere you want. !.5" pipe wont hurt a thing.

Thank you. Tank sits right next to well. 1 inch comes up from well pump then into csv then to brass tee to tank then 1 inch ball valve. This is where i was going to take off to building. Just did not know if it was better to tee from main on the way or at the tank but if it makes no difference i will catch the garage on the way to building. How come the well pump is 20 gpm but we got about 30gpm when tested?

Submersible pumps have a sweet spot where you are getting the most water and pressure using the least amount of electricity. That sweet spot is also a point where the pump is more comfortable. If you go too far left of the sweet spot, you are pressurizing the pump up but not getting much water. If you go to far right, the pump's motor can pull over it's rated amperage. This is all shown on most pump curves, like this one: http://www.pumpsandtanks.com/Curve-Charts/20_gpm_curve.htm