The city engineer's office will have the zoning map. There are numerous "legal, non-conforming" uses such as small businesses in residential areas, that are often grandfathered in. Also, zoning applies to land USE, not health and safety issues or building code issues.
I spent ten years on the zoning commission, including two years as chairman, and four years on the city/county planning board before the county messed that up. That was in addition to my being the city preservation officer for ten years, which requires a thorough knowledge of city codes as they apply to buildings.
I know more about zoning than I ever wanted to know.
[This message has been edited by Amorette F. Allison (6/5/2014)]