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. ! \7 U5 Z' d; {! R6 p, ^) n. [5 C+ ~: z+ H7 ^
Solution: turn off water supply and take the humidifier apart and clean it will stop the leaking.% I9 U/ p" W) {3 Q7 i7 Z
* q3 c8 o7 N& R% \& ?. d6 a & E, k1 J! C0 w- b& i$ N2 n* E( Z& pOtherwise, find a professional or change a new set.