經律異相 19.54

19.54

佛說是偈已。告諸比丘。從今不持漉水囊不聽行。若不持者犯。不犯者有清流水。或大河或泉水。從此寺至彼寺。二十里內不犯（出十誦律雜誦第三卷）。

After the Buddha spoke this gāthā, he addressed the monks: "From now on, traveling without carrying a water-filter bag is not permitted. If one does not carry it, one commits an offense. Exceptions where it is not an offense are when there is clear flowing water, a great river, or a spring; or when traveling from this monastery to that monastery within twenty li, it is not an offense." (Extracted from the third fascicle of the miscellaneous recitations of the Sarvāstivāda Vinaya).