Not all mopping robots separate clean from dirty water — and that matters

Cheaper mopping robots use a single water tank that drips onto the pad without rinsing it — so the mop gets dirtier with every pass across your floor. Models with separate clean and dirty water tanks actually wash the pad as they go, scrubbing with fresh water each time. The difference is basically a wet rag dragged around vs. an actual mop that cleans itself.