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. G0 `5 ^& i. u+ R% o' p: V% c. ?2 n! w0 C& e5 c
Solution: turn off water supply and take the humidifier apart and clean it will stop the leaking. $ j, z% _9 G+ ^5 ^3 @: C9 k1 V1 k
1 t! d) \9 y L/ cOtherwise, find a professional or change a new set.