Yes, if you have lots of hard floors and want genuinely clean results — especially with pets or kids. For light maintenance on already-clean floors, a simpler single-tank model may be sufficient.How does a dirty water tank keep floors cleaner?

The tank allows the robot to rinse its mop pad with fresh water after each pass, similar to a self-wringing mop bucket. Without it, the mop would just spread increasingly dirty water across your floors, leaving a grimy film.If you’ve just unboxed a robot vacuum with a mopping function and found not one but two water compartments, you’re probably staring at the second one thinking — what on earth is this for

Report 007922. Filed.