Coverage

All 58 California counties,
read from the county's own bill.

Coverage claims are easy to make and hard to check. Everything below is stated so you can test it on a parcel you pick, in a county you pick, against the county's own published document.

How a tax figure is produced

A property tax figure has one authority behind it, and it is not a data vendor. Every county is read one of two ways, and which one is a property of the county rather than a preference of ours.

Live per-parcel scrape
The county's own bill is read while the report is being built, for the counties whose systems answer fast enough to do it inside a request. That is most of them.
The county's roll, held in full
Where a county's system cannot be read inside a request — some require a full browser session and take half a minute — we hold that county's own assessment roll locally, obtained by public records request. Sacramento is 477,608 parcels; across twenty-two counties it is roughly two million.
Neither
The report is held. We do not publish a tax figure from a resold file under our own name and call it a determination.

Verified to the penny, and checked every morning

A county is only treated as verified when our total for a parcel matches the county's own published bill to the cent — total, ad valorem subtotal and direct-charge subtotal separately, so two errors cannot cancel out. A plausible number is not a verified one.

All 58 counties are then probed daily, and the probe asks whether a real bill came back rather than whether the call returned. That distinction matters: a scraper that quietly stops still lets a report build, with a number that still looks right.

Hazard layers

Every layer is determined against the parcel boundary, with the centroid result returned alongside it. Where the two disagree is where a determination gets challenged, so both travel together.

Special Flood Hazard Area
FEMA National Flood Hazard Layer
Nationwide
Area of Potential Flooding
Dam failure inundation — DWR and Cal OES
California
Very High Fire Hazard Severity Zone
CAL FIRE, including pending-adoption zones
California
Wildland / State Responsibility Area
CAL FIRE SRA
California
Earthquake Fault Zone
CGS Alquist-Priolo
California
Seismic Hazard Zone
CGS landslide and liquefaction
California
Naturally Occurring Asbestos
CGS ultramafic rock
California
Tsunami Inundation
CGS tsunami hazard area
California coast

Environmental databases

Eight, each screened at its standard radius, with every regulatory program inside it reported by name — including the ones that come back clean, because a reader comparing two reports needs to know a program was searched.

EPA Superfund
NPL, Proposed NPL, CERCLIS/SEMS, NFRAP
1 mile
EPA RCRA
CORRACTS, TSD facilities, generators
1 mile
EPA Toxic Release Inventory
TRI reporting facilities
1 mile
DTSC EnviroStor
State cleanup sites
1 mile
SWRCB GeoTracker
Leaking underground storage tanks
1/4 mile
SWRCB registered tanks
Underground storage tanks
1/4 mile
SWRCB Cleanup Program
Spills, leaks, investigations (SLIC)
1/2 mile
CalRecycle SWIS
Solid waste facilities
1/2 mile

Pick a parcel and we will run it against whatever you use today, and hand back a field-by-field comparison — including anywhere we come out worse.

Coverage — ParcelDataSource · ParcelDataSource