FWIW, Connecting the head intake directly to the freshwater system is a huge mistake. Somebody better reply with the requirements for separating the toilet water from the domestic water supply. I wouldn't even try this. Home toilets go to great lengths to prevent backflow. Like two large air gaps and a backflow valve. Marine toilets don't consider this in any way.
I seem to recall that Peggie Hall was very adamant against it and I for one would never do it. Never ever connect a fresh water line directly to a marine head without some form of backflow prevention. A check valve in the line is not going to do it. Only safe way is to put a atmospheric vacuum breaker in the fresh water line to the head.
On the other hand, lots of people are connecting to the sink drain and it does not seem to be a problem. Highly suggest you get your hands on Peggie's bokk. Good luck
I seem to recall that Peggie Hall was very adamant against it and I for one would never do it. Never ever connect a fresh water line directly to a marine head without some form of backflow prevention. A check valve in the line is not going to do it. Only safe way is to put a atmospheric vacuum breaker in the fresh water line to the head.
On the other hand, lots of people are connecting to the sink drain and it does not seem to be a problem. Highly suggest you get your hands on Peggie's bokk. Good luck