First, run a manual mop-washing cycle.
If the dock cannot wet the pads during washing, check the clean-water tank, dirty-water tank, cleaning tray and tray filter first. Roborock lists these as primary checks when Q Revo mop washing does not work.
Find the most likely cause
Are the mop pads completely dry after the robot starts mopping?
Touch both pads after 2–3 minutes of mopping on hard floor.
Try these fixes in order
Reseat the clean-water tank
Fill it with clean water, make sure the lid is fully closed, then push the tank down until it sits evenly.
Check the dirty-water tank
Empty it and reseat it. A poorly seated tank can interfere with the dock’s wash/extraction cycle.
Clean the tray and tray filter
Remove visible hair and debris. Q Revo’s cleaning tank is removable specifically so it can be maintained regularly.
Verify mop settings
Make sure mopping is enabled and test with a higher water-flow setting before assuming a hardware fault.
When to stop DIY
If the pump runs but water still does not move after tank/tray cleaning and two test cycles, avoid opening sealed pump or internal water-line assemblies unless you are qualified. Contact Roborock support or a repair technician.