Ever wondered what size riser you need to put for your water supply? Green builders do. Here is a good list of pipe sizes, lengths and resulting pressure.
Water pressure in Brooklyn is pretty good. The idea is to pick a pipe size that will give you good pressure even if a couple faucets are turned on at once. The required pressure by code in Brooklyn is 8psi. So if you have a line that feeds three faucets you want it to be able to give 24psi (3×8). That way when all three are on you won’t feel a big loss of pressure.
But you don’t want to put too large pipes in since that’s just a waste of materials.
If you get low flow faucets and shower heads you will be able to get away with less pressure because each head is pulling less water from the pipe. As Brooklyn becomes greener and more water conscious these kinds of things are important considerations for a green contractor or green plumber. Clients will depend on us to think about this stuff.
Another consideration: what size heating and cooling do you need when the house is super insulated? Don’t let the non-green plumber snow ball you into the “correct” sized boiler. They are basing their calculations on “standard” houses with pathetic amounts of insulation. Ideally you have a green plumber who knows about this.