Your system can be hooked up to the tap by whatever means; that doesn't matter. The automatic shut-off valve goes between the carbon block and the membrane on one side, and inline on your pure water line on the other side. Yes, paired with a float valve they stop floods, lol
I'm setting up a system that has four 55 gallon barrels (food quality of course) for my RO/DI system. Two will be RO/DI, one will be saltwater, and other one will have RO-only for drinking water until I hook the entire house up to RO.
Clayton