I would start by entering your address here:
Once you know what zone district you're in, click on the link (or navigate elsewhere) and it should open up the appropriate code sections in PDF. You'll have to look in the code to see what you can/cannot build there.
If you need any help with the details, PM me (or if you want it to be a fun public exercise, we could do it here too
EDIT: My guess is you're in the S-SU-F. If that's the case, it's sort of the classic larger-lot suburban zone district, and there's probably not much they can do.
There are also a lot of pockets of Arapahoe County in there... I'm assuming they're in Denver, though?