BT Pes 40a(10) :כל גב מיזליהו לא מחמצי‏ : as long as (the waters) are moving they do not cause leavening
See the entire entry for ˀzl vb. to go

BT Pes 40a(10) [print!] :דכל אגב מדלייהו לא מחמצי‏ : they do not ferment as long as they are absorbing
See the entire entry for miḏlē v.n. drawing water, absorbing