This bug is old news, but somehow seemed to never have been reported.
A Lavatory will use input water and produce output polluted water when pathing from the Dupe to the lavatory is interrupted. This produce a 6.7kg of excedent water, which should come from the Dupe bladder, but the Dupe bladder isn't emptied in this case.
This can be exploited to create 2kg/s of polluted water from a single Dupe. I attached a save file with just that exploit on max difficulty.
To fix that, a few propositions that don’t seem too hard to implement from an outsider view:
- The Lavatory should only count a use when a Dupe actually relieved itself.
- OR A Dupe could “make a mess” just after being interrupted from a Lavatory errand.
- Put a Lavatory behind a door that get automatically closed when a Dupe approach
- When a Dupe needs to use it, the Dupe will path to it, and get interrupted by the door closing
- When that happens, the Lavatory will count that as one use, and take in 5kg of water and output 11.7kg of polluted water, despite the fact that the Dupe didn’t relieve itself.