Q: What status do communal regulations have as minhag hamedinah?
A: The Poskim attribute special significance and authority to communal regulations regarding taxes and other essential communal matters, even if these regulations deviate from Torah law. Terumas Hadeshen (#342) explains that if every case were subject to halachic legislation, there would be constant strife in the community, so that the community members mutually forgo their halachic rights and accept the communal regulations that they establish (Rema C.M. 163:3).
He compares this to partners whose conditions and stipulations with each other are mutually binding even without a kinyan (Rema 176:3; C.M. 231:27-28).
This implies that communal regulations need to be established initially with the agreement of the entire community. However, Chazon Ish (B.B. 5:4) writes that the community has power equivalent to that of beis din, so that the consensus of the majority of the community suffices. Furthermore, the regulations are binding even if they are substandard, because this is still preferable to constant conflict.
