[Avodah] mikva use

[David Riceman]

RZS:

<<It's a machlokes rishonim. The Rambam holds that it's de'oraisa, so 
there's no need for a takanah to prevent it. The Ramban holds that it's 
derabanan, and the Rivash held like him, which is why he made his 
takanah that has been accepted by most communities.>>

Where does the Ramban say this? In his tshuva to Rabbeinu Yona (ed. 
Chavel, pp. 158-160) he clearly says that there is no issur, either 
d'orayysa or derabbanan.

It's true that he says that it's a really bad idea: "But you should warn 
them against pilegesh in your town [which R. Chavel takes to mean 
Toledo], because if they know that it's permitted they will they will 
act licentiously (yiznu v'yifritzu) and will have relations with them 
when they are nidos."

But the Ramban is clear that there is no issur derabbanan.  R Chavel 
notes that Rabbeinu Yona and the Rashba both disagreed with him about this.

David Riceman