Query Los Angeles County parcel and assessed-value data through the County Assessor's Open Data / GeoServices API
domain: data.lacounty.gov · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Locate the target dataset (e.g., Assessor Parcels) on the LA County Open Data Hub at data.lacounty.gov
Use the dataset's provided API endpoint (GeoServices/ArcGIS REST, WMS, or WFS depending on the dataset) rather than scraping the public-facing portal.assessor.lacounty.gov search UI
Query by parcel APN, address, or spatial bounding box depending on which query parameters the specific dataset's REST endpoint supports
Request the desired output format (GeoJSON, CSV, etc.) directly from the API rather than exporting through the UI
Cross-reference field definitions against the dataset's own metadata page, since attribute names vary by dataset and are not identical to RESO/MLS field names
Known gotchas
portal.assessor.lacounty.gov is a public search UI, not an API — automated access should go through the data.lacounty.gov ArcGIS Hub endpoints instead, or requests may be blocked as scraping
Assessed value data reflects Proposition 13 base-year assessments plus any inflation adjustments, not current market value, so it is not a substitute for an AVM
Dataset refresh cadence varies by dataset and is not guaranteed to be real-time; check each dataset's metadata for its last-updated field before treating results as current
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