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. ( X& }. I& h4 T h" }$ V9 j- F( K n- z! kSolution: turn off water supply and take the humidifier apart and clean it will stop the leaking.' d6 D2 i- n8 Z L1 _
/ s8 }5 X7 A: Z: d 7 @' z! v! O8 Y0 @( d4 B# V1 Y" nOtherwise, find a professional or change a new set.