Start with the waste tank seal.
Community reports repeatedly point to the dirty-water tank lid/gasket as a real cause of failed extraction, while Roborock’s routine maintenance guidance also makes tray/filter cleaning a first-line check.
Find why the tray will not drain
Does fresh water enter the tray during mop washing?
If yes, the supply side works and the fault is on the dirty-water return side.
Try these fixes in order
Reseat the waste tank
Empty it, close the lid completely and set it back into the dock.
Clean the lid gasket
Wipe the sealing surfaces so the tank can seal normally.
Clean the tray and filter
Remove debris from the parts designed for routine cleaning.
Run one controlled test
Watch whether standing water is now transferred to the waste tank.
Do not keep flooding the tray
If the tray remains full after the visible path and tank seal are checked, stop repeated wash cycles and arrange service instead of dismantling the dock.
Roborock Q Revo manual
Use Roborock’s maintenance and troubleshooting instructions as the primary reference before opening the dock or attempting internal pump repair.
Open official Q Revo manual