Hi,
I am building a new home in the country and have a 3000 gallon water tank 75 verticle above my (future) second story. I was going to have either 2" sch 40 pvc or 1 1/4" come down the 160 feet to my home. And then I wanted to know what is the largest copper pipe I could use inside the home to maximize pressure and also fit in the 2x6 walls. I live in Coco county, CAlifornia.
Cheers
Jimbo

Hey Jimbo,

Don't confuse pressure with volume and that's exactly what you're doing. The size of the pipe doesn't determine pressure. The size of the pipe determines the volume. Pressure is what pushes that volume. I'll tell you exactly how much pressure you'll have with a 75 foot head. For every foot of height water will gain .43302 pounds of pressure. 75 X .43302 = 32.47 of PSI. Less a little for the 160 feet of line loss.
32 1/2 pounds isn't very much pressure so here's what you're going to hafta do. You have 3000 gallons of volume at your disposal. Run a 1 1/4 PVC line down from the tank to a "kicker pump" and bladder tank and install a pump control box set at 30/50. Run 1" plastic or copper from the pump for the service and 3/4" for the house mains. Use 1/2" for the branches with no more then three fixtures off a 1/2" branch.
Check my figures if you wish but I guarantee with 75 feet of head that's all yer going to git!