Starflyte...
The building setback along the rear property line is 10 feet; along the side it is 5 ft...at least here in my section of Sumter County.
There is a new feature on the Sumter County Property Appraiser website that lets you view a parcel map, i.e. how the lots in an area are laid out.
http://www.qpublic.net/sumter/
Search for a property by address; select the info for that property (will show you original price, lot size, house size, etc), then click on the button that says "Show Parcel Map"...in the upper left quadrant. This will show you the property in question and how the lot is configured along with others in the neighborhood. You can click on any property in the view (or zoom, pan to other areas) and get details about those properties.
Aside from these online tools, I would think the Sumter County Annex up at Morse and 466 would be able to show you any survey info.
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Maryland (DC Suburbs) - first 51 years

The Villages - next 51 years