四分律比丘含注戒本 2.571

2.571

尼同犯。不犯者：先不知；若無蟲想；若蟲麁，觸水使去；若漉水飲用者，無犯。

Bhikṣuṇīs commit the same offense. There is no offense: if one did not know beforehand; if one perceived there to be no insects; if the insects are large and one brushes the water so as to make them leave; or if one filters the water before drinking and using it—in these cases there is no offense.