Now that is what I expected SHOULD be happening (I was a programmer for 20 years and would have been how I would have done it). But I also would have locked out this water from the cooking system and only used what is on hand and/or available locally.
That's what I meant by it being a design error rather than it being an out and out bug. I just think that the developers missed the cooking system and it is taking what is being produced at all the sites and then making it available for the player... You can see that happening with the junk being shared between all the sites. As soon as your supply line is made then all the junk and building materials are shared between the two.
It's a shame there wasn't a detailed production/usage system listing for local and global. That way you can see where you need to produce more water at sites that have water sources to cover sites that can only be supported by hand pump wells. I now have a whole load of industrial purifiers pumping out the pure stuff at Sanctuary and a few others... and I am finally producing excess again.
Now back to that boathouse with 25... I wonder if they were draining my water because of the excess population and Brahmin. It only just came to me. Do Brahmin have to be fed/watered too?