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. " h, X) r3 a( R0 p& P8 G2 Y0 C * l D" {( N, ^Solution: turn off water supply and take the humidifier apart and clean it will stop the leaking. 2 \. v$ h: j" R' u0 x 0 q4 H- Z8 H* |1 T: B - Y4 F$ A5 W4 t- D/ k9 iOtherwise, find a professional or change a new set.