The city's zoning map was changed a few years back, and buildings that we're legally multi-units prior to any down zoning should be made legal non-conforming buildings.
If the attorney is looking for a A Certificate of Zoning Compliance, the certificate will likely cite the current zoning code and not account for legal non-conforming units. It certifies the number of residential dwelling units at the property that are legal under the Chicago Zoning Ordinance. RS3 specifically permits a two flat dwelling. You can verify permitted uses at: http://www.amlegal.com/nxt/gateway.dll/Illinois/chicagozonin
What you will want to investigate is number of dwelling units that the Department of Buildings currently have for your property. You can go to: http://www.cityofchicago.org/city/en/depts/bldgs/supp_info/f Send in the FOI and request the number of dwelling units. Check in with an attorney once you verify this to see what your next steps will be. It may be that your home was never legally a two unit. This is not uncommon for chicago, and an attorney, and perhaps an architect may be needed to help you understand how to best resolve the issue. Although Realtors deal with Zoning often, we are by no means experts in zoning.
Best of Luck.
Buyer's atty may also have gotten the zoning certification back from the zoning dept which indicates that the zoning dept does not recognize the building as a multi-unit.
Either way, your real estate agent needs to be marketing the property as a single family home rather than as a 2 or 3 flat.
Zoning issues are fairly complicated. I suggest you contact an attorney that specializes in real estate. An attorney I can highly recommend is Susan Malone. 312-726-2638.
How do you know it was incorrectly zoned? Is it in essence a single family & someone (the previous owner) told you it was a multi?
RS3 is for a single family dwelling. If it were a multi-family it would have an RM designation. I would suggest you contact an attorney for the ramifications question. Chances are there won't be any since this probably should have been addressed at title closing.
Unfortunately, this happens more often than you think. No-one checks for zoning until it's too late (usually when they want to sell). They simply take the previous owners word (who was probably told the same by the previous owner) for it.
Here is a website that may, at the very least, shed some light on zoning codes: http://www.clvn.org/pdf/zoningCodeSummary.pdf
Hope this helps & if I can be of further assistance or help your mama sell her home please do not hesitate to call on me. Good luck!
Evelyn S. Fred
Baird & Warner
If you give me the address I can do some homework, but if the property is on the market, her agent should know the answer.