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. " o- `9 c, |' Q8 [
2 p& M) I/ S% t. M( v8 I3 P, RSolution: turn off water supply and take the humidifier apart and clean it will stop the leaking. 8 f9 h! l3 U* j3 e( o# J 4 r6 @: w6 Z: G; Q, b( S $ G7 n3 @ c/ GOtherwise, find a professional or change a new set.