Question about iRobot Braava 390 T

Good day Bletry.sandro

This question cannot be answered conclusively, as it depends on various factors such as floor heating, floor structure, etc. Basically, the water fill is enough for one cleaning pass.
In dry mop mode (straight lines), Braava 390 T can clean up to 92m2 , or you can use the damp mop mode (forward and backward) in which up to 33m2 can be cleaned.

Best Regards
Your iRobot Team