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. % s# ^+ H2 r2 a6 m $ e* m: x4 a* Q1 ~, GSolution: turn off water supply and take the humidifier apart and clean it will stop the leaking. : ^1 L% }0 s) O* H% m4 r2 A" n. C5 ^5 C
2 @, Z0 Q) j' p8 Z! }5 c! x1 YOtherwise, find a professional or change a new set.