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. 9 u$ b3 V9 f, p! T4 j4 ~0 {2 `1 _3 {( n+ S5 B
Solution: turn off water supply and take the humidifier apart and clean it will stop the leaking.9 N" F5 Q2 ]* } K( u' z
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% @$ f& I8 y0 ^Otherwise, find a professional or change a new set.