四分律行事鈔資持記 3.371

3.371

三中。流出外者，即淨地外大界中；欲冷大界精潔，遮世譏嫌故。彼律因俗訶言，僧住與俗無別，故制不得。䊩，音番，淘米汁也。

In the third: "Flowing outside" means into the great boundary outside the pure ground; it is to make the great boundary pure and clean, warding off worldly ridicule. That Vinaya states that because laypeople criticized, saying that the monks' dwelling did not differ from laypeople's, it was prohibited and disallowed. Fān (䊩), pronounced fān, is rice-washing water.