Resources

Screening methodology

Parcel View clips each public GIS layer against the parcel polygon from the CA DWR Assessor Lightbox layer and reports approximate percent of lot covered and the attribute label (zone code, FLD_ZONE, FHSZ class, etc.). These are derived screening results; the underlying datasets remain with the originating agencies.

• Parcels — Statewide assessor parcel boundaries (DWR Lightbox).
• Zoning — CA LCI Statewide Zoning (North + South services merged).
• General Plan land use — CA LCI General Plan Land Use.
• Geology — CGS liquefaction + active fault traces (merged query).
• Soils — USDA NRCS SSURGO map units.
• FEMA flood / floodplain / floodway — FEMA NFHL; three rows filter the same national layer differently (all zones vs SFHA vs floodway).
• WUI — CAL FIRE Wildland-Urban Interface Code Applicability area.
• Fire LRA & SRA — CAL FIRE Fire Hazard Severity Zones (public GIS mirrors with statewide FRAP fallbacks).
• Extensions — DOC Williamson Act, Caltrans scenic highways & airports, NPS National Register polygons, CGS landslide & tsunami, DWR Bulletin 118 groundwater basins.

An empty screening row means no polygon from that public service intersected the parcel in the query — not a guarantee that the hazard or zoning classification is absent. Rural parcels, mapping scale limits, and service outages can produce false negatives.

How to verify before you rely on screening

1. Confirm APN, situs address, and jurisdiction (city vs unincorporated county) on the county assessor parcel viewer.
2. Open the official zoning / General Plan map on the city or county planning portal linked in the map app.
3. Check FEMA Map Service Center for current FIRM panel, SFHA status, and any LOMA/LOMR.
4. Review Natural Hazard Disclosure (NHD) and seller disclosures (Civil Code §1103 et seq.) for mapped flood, fire, fault, seismic, and dam-inundation categories.
5. Obtain written insurance quotes (including FAIR Plan/DIC if needed) and flood insurance if in SFHA.
6. For commercial, industrial, or gas-station sites, search DTSC EnviroStor and State Water Board GeoTracker; consider a Phase I ESA.
7. Consult licensed professionals (surveyor, geotechnical engineer, septic designer, attorney, title officer) as warranted.

Parcels & address search

Used to locate lots, draw parcel boundaries on the map, and run address or APN search.

Land use, zoning & planning

Zoning controls what can be built; General Plan land use is long-range policy. At launch, Parcel View screens zoning and General Plan using California LCI statewide GIS filtered to the parcel county. Always confirm the controlling designation on the official city or county zoning map — incorporated cities often have zoning that differs from unincorporated county layers.

Official county & city verification portals

Parcel View links each county to its planning portal so you can verify zoning, General Plan, permits, and CEQA on authoritative maps. We do not scrape those portals. Linking is for user verification only. These portals are not queried for automated screening at launch unless noted in a future product update.

In the map app, each of the 58 California counties links to that county's official planning portal for verification (assessor, zoning counter, CEQA, historic preservation). Examples:

• Los Angeles County Planning
• Alameda County Planning
• Permit Sonoma
• Yolo County Planning
• San Diego County PDS

Flood, fire, geology & soils

Natural hazard layers used on every California parcel screening.

Optional screening layers (all counties)

Extra topics included in every county pack when layers overlap a parcel.

Map display, chat & knowledge

Due diligence references (not automated in Parcel View)

These authoritative sources are commonly used in California real estate transactions but are not queried automatically by Parcel View screening. Review them separately when risk warrants.

Data licensing policy

Parcel View uses publicly available government GIS services and open datasets published by federal, state, and local agencies. Each dataset remains subject to its respective provider's terms, update schedule, and licensing requirements. Where permitted by the data publisher, we connect to machine-readable endpoints (FeatureServer, MapServer, APIs) — not scraped web pages — so layers stay maintainable and align with how agencies intend data to be consumed.

Certain datasets require attribution under the publisher's terms. Parcel View provides attribution throughout the application and on this Resources page.

Parcel boundaries come from the CA DWR Assessor Lightbox statewide public layer. Zoning, hazards, soils, and flood layers use federal and state open GIS (FEMA, CAL FIRE, USDA NRCS, CGS, LCI). County planning portals are linked for official verification — not scraped.

Intellectual property

Government datasets remain the property of their respective agencies. Parcel View does not claim ownership of public GIS data and provides attribution where required. Agency names are used solely for identification and attribution. Parcel View's software, derived screening presentations, curated knowledge text, and product branding remain Parcel View intellectual property, separate from the underlying public datasets.

Legal notices, accuracy & limitations

No agency affiliation or endorsement

Parcel View is an independent product. References to FEMA, CAL FIRE, USDA NRCS, California Geological Survey, Department of Water Resources, Department of Conservation, Esri, and other agencies are for attribution and user convenience only. No government agency sponsors, endorses, or guarantees Parcel View. Agency names and logos remain the property of their respective owners.

Third-party data & services

Parcel View accesses publicly available GIS web services and datasets provided by government agencies, and may display Esri or OpenStreetMap basemaps under their respective licenses. Availability, rate limits, service interruptions, or schema changes may affect results. Providers publish data under their own terms, accuracy standards, and update schedules. Esri geocoding is used for address suggestions only and requires an appropriate Esri license or API key; geocoded addresses are not government-sourced property records.

Screening limitations

• Parcel boundaries from assessor GIS may not match recorded legal descriptions or survey stakes.
• Intersect percentages are approximate and depend on map scale and polygon generalization.
• LCI zoning harmonization may lag recent rezonings or not reflect city-specific overlay zones.
• FEMA NFHL may be preliminary or outdated relative to the effective FIRM panel date.
• Extension layers (historic districts, scenic highways, airports) use statewide datasets that may omit local designations.
• Absence of a hit on a layer is not proof that a hazard or restriction does not apply.

Artificial intelligence

When enabled, chat responses may be generated by a third-party language model (including optional OpenAI) using Parcel View curated reference material. OpenAI is used solely to generate natural-language summaries and does not provide official property determinations. AI output can be wrong, incomplete, or outdated. Do not treat chat text as legal, engineering, environmental, insurance, or financial advice. See our Terms of Use and Privacy Policy for data handling when AI features are used.

Professional advice

Parcel View does not provide services requiring a California license (surveyor, engineer, architect, attorney, real estate broker, insurance agent, etc.). Hire qualified professionals and obtain written determinations from planning, building, fire, and environmental agencies before acquisition, construction, subdivision, or investment.

Report data issues

If you believe a public GIS layer is mislabeled or Parcel View misreports an intersection, email help@parcelview.co with the APN, county, layer name, and a link to the official source. We investigate routing and attribute mapping; we cannot change underlying agency data.

By using Parcel View you agree to our Terms of Use. This resources page supplements those terms and may be updated as data sources or product behavior change.