It is possible to mop polluted water from a clean water tank

put a pitcher pump in the tank touching the polluted water then have a bottle emptier set to pwater else where with autobottling on

Just in case it's not clear, I posted this in the bugs/exploits section. With the exception of this case, it is otherwise not possible to mop up a large body of water. And in real life I definitely can't first piss into a swimming pool and then get a sponge and clean it up just like that.

oh I misunderstood, yeah this has to do with quantities, any liquid of less than 150kg can be mopped up no matter its location, except for the fact that dupes wont path through more than 5 or so blocks of water to do a job, and the mob job will get kicked the moment the water floods in at more than 300kg without being dropped by a single mop action, you should end up with a bottle of pwater and a bottle of water.  What part of this is bugged?  I understand its not "like real life" but seriously tell me what part of this game is.......

I suggest the following fix: If this is caused by the fact that it's allowed to mop up tiles with less water than a set amount, then also check the tile above and below and if either of those has liquid of any type with a larger amount, then disallow mopping up the original tile. I think that should take care of the most cases.