Coverage & provenance
What we know, and where it's thin
Most zoning products present their coverage as a single confident number. Ours isn't one thing: a parcel in Chicago and a district roster in Cheyenne are separated by several orders of confidence, and you can only use the second properly if you know that. This page says which is which, names the gaps, and tells you how to check us.
1 · Confidence, by layer
| Layer | Scale | Confidence | Use it for |
|---|---|---|---|
| Chicago parcel analysis | 2.62M255 jurisdictions | Highest — real parcel geometry against a field-cited ordinance extraction | Screening and underwriting a specific site, then confirming with the City |
| Chicago district reference | 53 districts | High — every field cited to its section, though the source and date vary by district | Knowing what a district permits before you have a parcel |
| Parcel + district lookup | 51 cities31 states | Low-moderate — real parcel geometry matched to a self-hosted district map, no cited bulk standards | Confirming a lot's district and boundary before you dig into the ordinance yourself |
| State zoning law | 50 states | Moderate — statute-level, verified against the enabling act | Understanding who holds the zoning power and under what constraints |
| City district rosters | 306 cities3,904 districts | Orientation — roster-level, checked against municipal GIS where reachable | Learning the vocabulary of a market you're new to |
The line that matters
Only the first row is parcel-grade — real geometry read against a cited ordinance extraction — and it currently exists for the Chicago metro; Illinois is the only state where that full analysis is live. Raw parcel geometry reaches further than that: 51 of our 59 mapped cities, across 31 states, will resolve an address to a real parcel and district today — but that lookup stops there. South Bend, Indiana is the one exception with curated, per-field-verified bulk standards (12 districts), and even that carries no citations-grade report. Everything else tells you what a district is called and broadly permits. None of it tells you what your specific lot can hold; for that you need the parcel's actual zoning from the jurisdiction.
2 · How the city rosters were checked
Each city's district roster was drafted from that city's zoning ordinance, then checked against the city's own published zoning GIS layer — the district codes actually painted on the official map. The map is the referee: it is produced independently of how we read the code, so it catches the errors a careful re-read of the code would not.
Where the map and the draft disagreed, the map won and the roster was corrected. Where no public layer could be reached, the ordinance-sourced roster was kept rather than dropped — a roster from the code is still useful — but it has not had the independent check, and it should be treated as the weakest thing on this site.
In progress
We are adding a per-city confirmation flag to the published dataset so that every city guide states its own verification status on the page, rather than describing the process in aggregate here. Until that lands, treat any city roster as unconfirmed unless you have checked it against the city's own map — which every city guide links.
3 · Cities we publish no roster for
21 of our 327 city guides carry no district list. That's deliberate in one case and a gap in the rest, and the two are worth keeping apart:
No conventional zoning
- Houston, Texas — regulates land use through deed restrictions, subdivision platting and development ordinances rather than a zoning map. There is no district roster to publish, and any source that gives you one for it is wrong.
Roster not established (20)
These cities do have zoning. We could not establish a district roster we were confident enough to print, so we publish the administrative picture and the official source instead of a guess.
- Lakewood, Colorado
- Bridgeport, Connecticut
- Danbury, Connecticut
- New Haven, Connecticut
- Norwalk, Connecticut
- Waterbury, Connecticut
- Middletown, Delaware
- Milford, Delaware
- Newark, Delaware
- Seaford, Delaware
- Athens, Georgia
- Columbus, Georgia
- Savannah, Georgia
- Allentown, Pennsylvania
- Scranton, Pennsylvania
- Cranston, Rhode Island
- East Providence, Rhode Island
- Pawtucket, Rhode Island
- Rock Hill, South Carolina
- Cheyenne, Wyoming
4 · Known weak points
- Ordinance-only districts. A handful of districts appear in a city's code but not on its published map layer. We keep them, because a district can be adopted and not yet applied to any parcel — but they are the ones most likely to be stale.
- Recently rezoned and annexed parcels. Third-party GIS mirrors lag the city's own map. For a live deal, pull the parcel from the jurisdiction, not from any aggregator including this one.
- Planned developments and overlays. A parcel inside a planned development is governed by that ordinance, not by its base district — and base-district figures will overstate or understate what it permits, sometimes dramatically.
- Topics outside the corpus. ARO rates, coach-house dimensional standards and DOH pre-certification are not in our verified corpus and we publish no numbers for them. Why, and what we do say →
5 · Found something wrong?
Send the page URL and what the jurisdiction's own source says to team@realdevelop.io. City roster corrections are checked against that city's published zoning layer, Chicago corrections against the ordinance text. Where a correction narrows what we can claim, we narrow the claim rather than defend the old one.
Common questions
- Which part of this data can I underwrite on?
- The Chicago parcel layer, and even then as analysis rather than as the City’s position. The state and city reference pages are orientation — what districts exist, who administers them, what they broadly permit. They are not a substitute for pulling the parcel’s actual zoning from the jurisdiction.
- Why do some cities have no district list?
- Two different reasons, and we keep them separate. Houston has no conventional zoning ordinance at all, so there is no roster to publish. The other 20 are gaps in our data: we could not establish a roster we were confident enough in to print. Those pages still cover how zoning is administered in the city and point at the official source.
- How do I check a city page against the real thing?
- Every city guide names that city’s official zoning map and code, which is the authoritative source and outranks anything here. If they disagree, the city is right and we would like to know — email us the page and what you found.
- Does coverage expand?
- The full-report layer expands in the order demand does — Illinois went first because that is where the deals were, and each state page carries a waitlist that decides what comes next. The reference layer already covers all 50 states, and raw parcel data now reaches 31 of them (10.2M parcels) — though only as a district-and-boundary lookup in a mapped city, not a report.