In Masechet Parah, in Perek Chet (Chapter Eight), I’ll tell you where you get to Mishnah Tet: the waters that are used for red water. So we learned in the previous Mishnah that it has to be water from a wellspring. However, if it’s which literally means damaged waters, it’s no good. So the Gemara says, “What are damaged waters?” Salty. So if they’re salty, they’re not fit to drink. Or they are hot waters, lukewarm, and therefore unfit for drinking. Therefore, they cannot be called living waters. The Bartenura says they cause damage. The Gemara says you shouldn’t drink lukewarm water.
Hamayim hamechazvin. Mechazvin means they occasionally dry up. Like the Pasuk (verse) says, lo yechazevu meimav (its waters do not fail) in Yeshayahu. So the question then is: it’s not a constant wellspring. Sometimes it’s alive, and sometimes it goes dormant. So it’s called hamayim hamechazvin. What makes mayim mechazvin? Hamechazvin me’achat b’shavua (those failing once in seven years). That means it has to be so continuous, even if it stops once every seven years. Shavua does not mean a week of it. Shavua means a Shemitah (sabbatical year) cycle. If you look at the Bartenura, if it stops once every 50 years, that’s still considered Mayim Chayim (living waters).
But let’s say the reason why it stops is that soldiers, during a war, are going and drinking water from the well and damaging it. That does not make it mechazvin. Or let’s say there’s a drought, and that’s why it stops. So that’s an external reason. Then, if you look at the Bartenura on that, the soldiers of the armies drink from the wellsprings and ruin them, or there is a time of drought. The first opinion says that’s external. That’s not going to be considered. However, Rabbi Yehudah posel (disqualifies). The halakha (Jewish law) is ke-Rabbi Yehudah.