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. * Z* d$ a- [' Z- w" P0 f , V6 C" f: B( ^* }$ dSolution: turn off water supply and take the humidifier apart and clean it will stop the leaking.& m+ M Z" f- Y! L) w! U
( R- Y F s. t) L% M * [! ]% x7 t+ F v' @8 v& lOtherwise, find a professional or change a new set.