אסור לקרות כנגד מי רגלים עד שיטיל לתוכן רביעית מים ואז מותר ולא שנא על גבי קרקע לא שנא בכלי ובלבד שלא יהא עביט המיוחד להם [ודין עביט ע"ל סימן פ"ז] לא שנא היו הם בכלי תחל' וניתן עליהם מים לא שנא המים בכלי תחל':

Not to Recite [the Recitation of the Shema] Opposite Urine - Containing 2 Se'ifim It is forbidden to recite opposite urine until one has poured a revi-it of water into it, and then it is permitted. And it makes no difference whether it is on the surface of the ground or in a vessel - as long as it is not in a special chamber pot that's designated for it [And for the law of the chamber pot see below Siman 87]. It makes no difference whether it was in a vessel first and water was poured into it or the water is in the vessel first.

A revi-it [of water], that they said [is required to be poured onto urine in order to render it permissible to pray in front of] is for one urination, and for two times (ie. two urinations), two revi-i-ot [are required], and for three [urinations], three [revi'ot are required]Rem"a: And so on and so on.