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. % T! i; l! w5 B3 _. B 8 N1 v+ p# g9 V- oSolution: turn off water supply and take the humidifier apart and clean it will stop the leaking. 4 e! ~$ A: N, h0 m/ }8 j [# `) r* ]- o7 Q8 h% @/ n- v# u2 z+ j, k5 O, r2 ? O" g; J
Otherwise, find a professional or change a new set.