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. 4 \# X9 c# }5 h% \$ Y6 w0 J! a: J; H# J; B+ Q( x
Solution: turn off water supply and take the humidifier apart and clean it will stop the leaking. 6 c- M4 M+ j# T, h& Q- _ L; N, v6 i! T& d# O " N, ^2 f* n5 K3 j4 W4 oOtherwise, find a professional or change a new set.