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Buying a house — the 12-dimension data checklist before you sign
A title search covers liens. An inspection covers structure. Neither covers the surrounding neighborhood-data picture. Here's the 12-dimension checklist zipradar federates so a buyer can read a place before reading the contract.
Published 2026-04-25 · Last reviewed 2026-05-13 · methodology
Why 12 dimensions
Real-estate listings show price, square footage, bed/bath count, and a few photos. They never show drinking-water violations, neighborhood deed-turnover rates, lead-pipe replacement obligations, or whether the parcel sits in a FEMA AE zone.
Each of the 12 dimensions zipradar federates is sourced from a different regulatory body. Together they answer the question 'what's actually true about this place?' instead of 'what does the listing say?'
The 12 questions every buyer should answer
1. Drinking water — does the utility have recent EPA SDWIS violations or LCRR lead-service-line obligations?
2. Flood zone — what's the FEMA NFHL zone (X / AE / VE / etc.) at this address, and what's the Risk Rating 2.0 premium?
3. Wildfire — what's the USFS Wildfire Hazard Potential, and does the address sit in the WUI?
4. Air quality — what's the multi-year AQI history from EPA AirNow, and does the area face annual smoke seasons?
5. Crime — what's the FBI UCR/NIBRS pattern at the agency-jurisdiction level (treat as orientation, not gospel)?
6. Schools — which NCES district, which feeder schools, what's the student-teacher ratio?
7. Radon — what's the EPA Radon Zone (1, 2, or 3), and is testing required at sale in this state?
8. Lead pipes — does the utility have an LCRR-flagged service-line replacement obligation that affects this address?
9. Property tax — what's the millage rate, current assessment, and does the prior owner's homestead transfer (it doesn't)?
10. Deed activity — what's the ZIP-level turnover trend? Spike in trustee deeds = early distress signal.
11. Zoning — what's the parcel's zoning code, and are there special overlays (historic, flood, environmental)?
12. Sex-offender registry — deep-link only to NSOPW; check before you commit, fresh + jurisdictional.
What the listing won't tell you
Sellers + listing agents disclose what state law requires, nothing more. State requirements vary widely. Florida + California have strong disclosure laws; many states have weak ones.
Even strong disclosure laws cap at 'what the seller knew' — they don't capture data the seller never looked at. zipradar's role is to federate the public-records data the seller may not even know exists.
What zipradar shows
Per address (or ZIP, when address-resolution isn't yet available): all 12 dimensions on one page, each with its source citation, refresh cadence, and limitations.
Where the data is too thin or jurisdictional, we say so explicitly — buyers shouldn't conflate 'no flag' with 'no risk'.
Last-verified timestamp on every page tells you exactly when the data was last refreshed.
Related zipradar topics
More from /learn/
- Flood zones explained — what AE, X, and VE actually mean
- EPA Radon Zones — what 1, 2, and 3 mean and when you should test
- FBI UCR and NIBRS — what crime statistics actually show (and don't)
- Lead and Copper Rule 2024 — the federal lead-pipe inventory mandate
- Property tax millage — what 'mill' means and how your bill is computed
- AQI explained — what 50, 100, 150 actually mean for your lungs
- School district boundaries — how to confirm yours and why it matters
- Wildfire Hazard Potential — what the USFS scale means and how to defend your home
- EPA SDWIS — how to read drinking-water violations and what they actually mean
- Deed records — what they show and what they don't
- Zoning codes — what R-1, C-2, M-1, MU mean and why your house is one
- Homestead exemption — state-by-state property tax savings
- Reading FBI UCR national crime trends — what 2020–2025 actually shows
- AirNow + wildfire smoke — when AQI is a real-time tool
- Radon and real estate — what disclosure laws and home tests actually require
- Wildfire insurance in 2026 — why premiums spiked and what to do
- NCES Common Core of Data — what district boundaries actually mean for buyers
- EPA SDWIS — reading drinking-water violations without panicking
- FEMA flood zones — AE vs. X vs. VE in plain English
- County assessor data — how millage rates and assessments actually combine
- NSOPW — why zipradar deep-links instead of caching the registry
- FEMA LOMA — when your home is wrongly in a flood zone (and how to appeal)
- NCES SABS — the only authoritative US school attendance map
- Deed activity by ZIP — what aggregated transfers tell you about market trends
- Private well water — what to test when EPA SDWIS doesn't cover you
- County recorder vs. county assessor — they sound the same, they're not
- Zoning overlays — historic, flood, environmental layers that change what you can build
- PFAS in drinking water — what 2024's new MCLs actually mean
- Lead in paint vs. lead in pipes — same metal, different exposure
- EPA Superfund + Brownfields — what 'contaminated site nearby' actually means
- Property tax escrow — why your monthly payment changes after you close
- AQI thresholds — what 'unhealthy for sensitive groups' actually means for you
- HOA + deed restrictions vs. zoning — three regimes that govern what you can do
- Data staleness — when to re-check zipradar before making a decision
- EPA AirNow — when to watch for particulates vs. ozone
- USGS earthquake hazard maps — when separate earthquake insurance is worth it
- Septic systems — what they fail on, what tests cost, when they're a deal-breaker
- Title insurance — what it actually covers, why it's a one-time premium, and why you can't skip it
- Closing day — what actually happens + the documents you'll sign
- Radon disclosure during real-estate transactions — state-by-state
- Mello-Roos + special tax districts — the property-tax extras you didn't see
- Groundwater vs municipal water — which does your address have, and how to tell
- Defensible space zones 0/1/2 — California's 100-foot rule + what works in practice
- Base Flood Elevation (BFE) — the number that decides flood insurance
- Tornado risk by region — wind zones, safe rooms, and roof rating
- Hurricane evacuation zones and storm-surge maps — what the colors mean
- Drought, water rights, and private wells — when your tap runs dry
- FCC broadband data — checking real internet speed before you buy
- EV charging access by ZIP — DOE AFDC data + home Level-2 install
- Walk Score, Bike Score, Transit Score — what they actually measure
- Noise pollution maps — airports, highways, freight rail by address
- First-time homebuyer programs — federal + state + local stack
- Abandoned property + tax sales — buying via county auction
- Extreme heat days + cooling equity — climate risk by ZIP
- Permit history + unpermitted work — what to verify before close
- Fixed-rate vs ARM — which mortgage type fits when
- Closing costs explained — what the buyer typically pays
- Earnest money — how much, when refundable, where it goes
- FHA vs conventional — when each loan makes sense in 2026