A significant amount of zoning is about what type of housing you can build where, how much of it you can build, and how you have to build it.

For example, in Berkeley California, which was one of the first cities to implement "exclusionary zoning" has roughly the following zoning restrictions:

* R-1: One home per lot or estate, only. Bans apartments in 49% of the city.

* R-1A: One home per lot or estate, unless the parcel exceeds 2,400 SF which allows for an additional home.

* R-2: Two homes on one parcel, only.

* R-2A: One home per every 1,650 square feet on a parcel. A typical residential parcel in Berkeley is about 5,300 square ft thus commonly three homes maximum.

[source](https://darrellowens.substack.com/p/berkeleys-upzoning-would...)