In Oxygen Not Included, you might so unlucky as to be in a generated world that has pockets of contaminated water instead of the fresh stuff your duplicants can actually use. Or, you know, your duplicants are disgusting and peed so much it spread everywhere and even dripped into your water supply.
Whatever the case may be, contaminated water can be fixed, don’t fret! If it’s around your colony’s floors, simply hit the mop command on the bottom right of your screen and drag it across all the tiles affected by that gross pee. Your colonists will walk over and start mopping it right up. It will be a tiny bit of work and you’ll be free of the nastiness.
But if it’s in your water, things change a bit. If it’s just one block, you could send your colonist in to mop that one spot. But you need to watch them to make sure they don’t mop forever and waste up all of your water. You need to cancel the action when they’ve mopped up all of the contamination. It’s weird, but it works.
If you have a much bigger contamination problem, your best bet will be to build a Water Purifier that, using pipes and sand, will purify your water. You simply place it in your colony, then put a pipe from the contaminated water (with a water pump there) into the purifier, and then another pipe line running from the purifier into an area you’d want the fresh water to drip into. (Don’t forget to place your liquid vent so that it can drip.)
Combine this method with your lavatory and you’ll have your duplicants’ pee turning into fresh water constantly! So long as you have sand, of course.
For more help with Oxygen Not Included, be sure to check back to Twinfinite for guides and tips!