Mikvaos 4:5 - 5:1

השקת (a grooved stone to receive and carry off the overflow of a well, sink, trough) – a hollowed-out stone that is on the rim of the spring. And the water enters into it through a cavity/hole in its wall, and provide water for the cattle in it.

אין ממלאים ממנה (see also Tractate Parah, Chapter 5, Mishnah 7) – [and they don’t draw from it] water for the waters of purification (which were mixed with the ashes of the red heifer, which was used to purify people and vessels that became ritually impurity with impurity imparted by a corpse).

ואין מקדשין בה – they don’t places the ashes of the heifer on the water that is in it, for it is not considered a utensil. But here, we are speaking of an attached rock that was hollowed out/made into a receptacle, and even something detached that was attached and then ultimately hollowed out/made into a receptacle, since it did not have upon it the designation/status of a utensil while detached, it is not considered a utensil.

ואינה צריכה צמיד פתיל (and it doesn’t require being closely covered with a lid) – if it is in the tent of a dead person (i.e., corpse), it saves what is inside it with a covering alone without being closely covered with a lid, because it is not considered a utensil but rather like a cistern or a subterranean masoned store-room, that saves what is in it with a covering alone.

ואינה פוסלת את המקוה – if rain water fell from inside it to a Mikveh, they are not considered drawn waters to invalidate the Mikveh/ritual bath.

וכמה יהא הנקב – to neutralize it from the law of being a utensil s that it does not invalidate the Mikveh from the reason of drawn [water].

כשפופרת הנאד (like the tube – i.e., mouthpiece – of the leather bottle) – and its measurement is that they would be two fingers of the hand closest to the thumb that return in their width at the extension within the incision.

וכל טהרות של ירושלים נטבלים על גבה – that they immerse within it and make them pure, but there weren’t forty Seah [of water] in the grooved stone/trough [to receive and carry off the overflow] but rather a complete Mikveh was at its side and the waters of the grooved stone/trough mix with it through the incision in the tube/mouthpiece [of the leather bottle].

עד שתפחת רובה – even if there is in the incision like that of a tube of a leather bottle, it always has the status/designation of a utensil upon it until its greater part will be broken down.

מעין שהעבירו על גבי השוקת – which is a utensil, and not the trough/grooved stone that is in the rock.

פסול – to immerse in the water that is within the trough and in the water that leaves and passes from the trough outwards, since all of the waters of the spring spill into the trough. But if the waters of the spring pass on the rim of the trough a bit, even though that some of them pass into the trough, it is kosher/fit to immerse in the waters that are on the rim of the trough or outside of it, for the spring purifies with a miniscule amount.

והפסיקו – for the waters of a pool are not attached to the spring.

הרי הוא כמקוה – but it doesn’t purify with a miniscule amount until there will be there forty Seah.

חזר והמשיכו – that he attached the waters of the spring to the pool.

פסול לזבים – that already stopped up their living [waters]. But regarding those with gonorrhea and lepers and waters of purification [mixed with the ashes of the red heifer for those made impure through contact with a corpse], it is written concerning them [that they require] potable, running spring water (see also Tractate Mikvaot, Chapter 1, Mishnah 8).