I've got a vacant, oddly-shaped 1.4-acre lot in Georgia that runs the full length of a city block, with frontage on two different streets. On paper, that screamed "split it into two lots and sell each one separately." I reached out to a survey firm to get a quote for exactly that.
The surveyor's first response wasn't a price. It was a question: had I checked with Planning & Zoning about a stream running through the property?
Doing the homework before spending the money
Instead of just asking him to explain further, I pulled the county's own parcel and topo map myself. There it was — a visible stream line cutting through the narrower end of the lot, right where I'd planned to put the second building site.
That sent me to the actual zoning ordinance. Turned out the city requires a 75-foot no-disturb buffer on either side of any stream, plus a 150-foot setback before you can put up anything with a foundation or pavement. Once I actually did that math against the width of my lot at the narrow end, there was a real chance that entire section had little to no buildable ground left outside the buffer.
Why this matters before you pay for anything
A subdivision survey and a formal engineering review cost real money. Before committing to that spend, it was worth an hour with free public GIS data to figure out whether the plan I had in mind was even physically possible. It turns out my "two-lot" plan was likely a "one-lot-plus-greenspace" plan all along — a materially different outcome for the economics of the deal.
I'm still getting the actual field survey done to nail down the exact buildable line (assessor maps are illustrative, not survey-grade), but I went into that conversation already understanding the real constraint, instead of finding out after paying for a plan that couldn't work.
The takeaway
Before you pay a professional to plan anything on a piece of land, spend twenty minutes with your county's own public GIS/parcel viewer first. Topography, water features, and zoning overlays are often sitting right there for free, and they can save you from spending real money chasing a plan the land was never going to support.