Harvested rainwater for non potable use in the home

[wyatt]

Are you saying that below 10 psi the valve wouldn't open? or is that just all the lower you tried?
By the way, 1 psi = 27.7 inches of water, so if 10 psi is required to open the valve, you would need about 23 feet of head to operate the system, which would mean even in the attic you would need a pressure boost for bathrooms directly below.