The clean and dirty water tanks work exactly like a kitchen sink — fill one, drain the other

This is one of those questions that feels dumb to ask but is completely valid if you’ve never owned a robot mop before. The answer is straightforward: fill the clean water tank with fresh water, and empty the dirty water tank after each use. Think of it like a kitchen sink — you’ve got a clean side and a drain side, and mixing them up defeats the whole purpose. The clean tank is usually clearly marked and has a cap you open for filling. The dirty tank collects whatever the mop picked up off your floors, and if you forget to empty it, it will start to smell within a day or two. Set a reminder for the first few times and it becomes muscle memory fast.