All righty, I replaced one of my Electric Jabsco toilets, rebuilt the other. As I was reading the instructions I noticed that Jabsco says to NOT have the toilets connected to your fresh water system.......well, that is exactly how mine were plumbed. The Fresh water system supplies the toilets and all the faucets and showers.
This boat was new to me this summer, its a 1979 Bluewater Sports Sedan.

My question, can I install some kind of check valve in the supply line to keep from cross contaminating, or should I set up a whole separate water supply for the toilets. Currently, they are only supplied through the boats fresh water system.