It is possible that the shut-off valve was blocked by the cumulated white stuff. As a result, water supply can not be stopped even when water level is high. . @9 ]) B- K4 I/ ~: H, g% { 0 A& j5 K5 }. ?; z8 h) _Solution: turn off water supply and take the humidifier apart and clean it will stop the leaking.+ ]0 X# g G; }0 F$ M; k
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Otherwise, find a professional or change a new set.