DIAGNOSIS The water pump is not activating or the water path is blocked. This is often due to an incorrect mop attachment, a closed water valve setting, or a clog in the system.
FIX First, confirm the mop pad plate is correctly attached; you should hear a distinct click. In the Roborock app, go to the cleaning settings. Set the Water Flow to a higher setting like 'Intense' or 'High'. Manually trigger a mopping session to test. Ensure the clean water tank is above the minimum line.
IF THAT DIDN'T WORK A physical blockage is likely. Remove the water tank. Check the tank's outlet valve for debris. Remove the mop pad and plate. Inspect the robot's water distribution nozzles on the underside for mineral deposits or blockage. Use a pin or toothpick to gently clear any visible obstruction.
HEADS UP Always remove the mop attachment for vacuum-only runs. Using the mop on carpets with the water flow on can cause internal damage and mold. The mop pad plate must be securely installed for the water valve to open.