How lotcheck works
lotcheck turns a Georgia street address into a plain-language site report: flood zone, elevation and slope, wetlands, jurisdiction, soils, and (in supported counties) parcel detail. It is built on free, public government data. It is a screening tool, not a survey or a flood determination. See the limits and disclaimer below.
The pipeline is deterministic
When you run a report, lotcheck geocodes the address, then queries each data source independently and assembles the result. There is no AI in the data path: every number and classification you see comes straight from a government dataset, and each card names its own source. If one source is slow or down, that card shows an error and the rest of the report still returns.
Two optional features do use a language model, and they are clearly separate from the data: the plain-English summary and LotCheck Pro.
Where the data comes from
Nearly all of these are free, public APIs operated by federal agencies, the state, or counties; the one exception is the Pro-only house data, which comes from a commercial property-records provider. lotcheck does not add or invent data; it reads these and presents them.
| Report card | Source | What it provides |
|---|---|---|
| Flood zone | FEMA National Flood Hazard Layer (NFHL) | The mapped FEMA flood zone and whether the point is in a Special Flood Hazard Area. |
| Elevation & slope | USGS 3DEP elevation service (EPQS as a fallback) | Ground elevation sampled across the lot, from which relief and max gradient are computed. |
| Wetlands | National Wetlands Inventory (USFWS wetlands raster) | Whether mapped wetlands fall at this point or within a ~500 m spot-check around it. |
| Jurisdiction | U.S. Census TIGERweb | Whether the point is in an incorporated city or unincorporated county. |
| Soils | USDA SSURGO, via Soil Data Access | The dominant mapped soil, drainage class, and hydrologic group. |
| Geocoding | U.S. Census Geocoder | Turns the address into coordinates, the county, and the FIPS code. |
| County parcel | Each county's own public GIS | Parcel boundary, acreage, zoning, and (Cherokee only) utilities, permits, and future-conditions floodplain. |
| House & structure (Pro) | County assessor property records, via RentCast | For signed-in Pro members: beds/baths, square footage, year built, features, HOA, tax assessments, and sale history for the structure on the lot, plus an optional on-demand value & rent estimate (an AVM — a statistical model, not an appraisal). Owner names are never shown from this source. |
| Map tiles | OpenStreetMap | The background map shown on screen and in the printed report. |
County coverage
Federal and state data (flood, elevation, wetlands, jurisdiction, soils) covers every Georgia address. Parcel detail comes from each county's own GIS, which lotcheck currently reads for 16 Georgia counties: Cherokee, Clarke, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Muscogee, Paulding, Richmond, and Rockdale. Cherokee additionally returns utility lines, permits, and future-conditions floodplain. Addresses outside those counties get the full federal and state report without the parcel card.
What it can and cannot tell you
- Geocoding can land on the wrong spot. The free address data lags new streets and subdivisions, so a brand-new street can be snapped to a similarly-named older one. lotcheck warns you when the matched street differs from the one you typed, and gives you a Google Maps link to confirm. Always sanity-check the marker on the map.
- FEMA maps can be out of date, revised, or simply unmapped. The absence of a mapped flood zone is not a guarantee of no flood risk.
- There is no septic or perc-test data anywhere in public layers. Soil drainage class is only a proxy for septic suitability, never a result.
- Soils and wetlands are mapped at landscape scale, not at the scale of a single building pad, and the elevation model cannot see a rock ledge, a soft spot, or a sinkhole.
- County GIS can lag the authoritative county portal. Acreage, zoning, and utility lines are read from the GIS and should be confirmed for anything important.
In short: lotcheck is a fast first screen. Anything you are going to rely on should be confirmed by a licensed surveyor, the county, and a FEMA determination.
The optional plain-English summary
The "Plain-English summary" checkbox writes a short paragraph describing the data already computed above it. It runs on a small open-source model on our server, using a key we hold and pay for, and it is rate-limited and spend-capped. It only ever sees the report data, never anything about you, and it is purely a readability convenience. You can turn it off.
LotCheck Pro (members)
LotCheck Pro is an optional deeper analysis: a frontier Claude model writes a buildability "read" over the report data, and members can reveal the parcel's owner and its neighboring lots. It is login-gated — you sign in, and the analysis runs on lotcheck's own server using a dedicated, spend-capped Anthropic key we hold and pay for. You do not bring or paste an API key.
- You sign in; the server verifies you. Your login is a token issued by our accounts service (PocketBase); the lotcheck server checks it — and that your account is a Pro member — on every Pro request before doing anything.
- The Anthropic key stays on our server. It never reaches your browser. The server sends the report data to Anthropic using that one capped key; the model is fixed server-side and the output is length- and rate-limited.
- What the model sees. Only the report data for the parcel (the same public data shown on the page) — never anything about you.
- The "Market & area context" toggle lets the model run a few web searches for nearby listing and sale context. It is off by default; turn it on and hit Regenerate for a slower, search-grounded memo.
Support lotcheck
lotcheck is free to use, with no account required, no ads, and nothing for sale. It does have real monthly costs, all paid personally: the server it runs on, the property-records data behind the Pro house details, and the AI analysis behind the summary and the Pro read. If lotcheck saved you some legwork and you'd like to help keep it running, you can leave a tip on Ko-fi. Tips are entirely optional and unlock nothing. Every feature works the same whether you tip or not.
Privacy
- No account, no login, no tracking pixels.
- We keep minimal, short-lived request information (such as the rounded coordinates of a lookup) to cache results and to rate-limit abuse. We do not sell data.
- Reports are cached by approximate location so a popular address does not re-hit the upstream services on every view. The cache holds the public report data, nothing about who looked it up.
- LotCheck Pro runs on our server-held, spend-capped key — there is no Anthropic API key in your browser. See above.
Disclaimer
lotcheck is informational only. It is not a survey, a flood determination, a title search, a septic approval, or professional due diligence, and it does not tell you whether to buy. Verify flood status through a FEMA Letter of Map Amendment and a licensed surveyor, confirm parcel and zoning details with the county and city, and have a perc test and geotechnical investigation done where they matter, before relying on anything here.