Counties · CA
Counties in California
13 California counties live on zipradar today, covering 29 ZIP codes across Berkeley, Beverly Hills, Cupertino, Fresno, La Jolla, Laguna Beach, Long Beach, Los Angeles, Menlo Park, Mill Valley, Monterey, Newport Beach, Oakland, Pacific Palisades, Palo Alto, Sacramento, San Diego, San Francisco, San Jose, Santa Barbara, Santa Clara, Santa Cruz, Santa Monica, and Tiburon. County-level data anchors property tax (county assessor), deed activity (county recorder), and the EPA Map of Radon Zones.
CA
Alameda County
3 ZIP codes
CA
Fresno County
1 ZIP code
CA
Los Angeles County
6 ZIP codes
CA
Marin County
2 ZIP codes
CA
Monterey County
1 ZIP code
CA
Orange County
2 ZIP codes
CA
Sacramento County
2 ZIP codes
CA
San Diego County
2 ZIP codes
CA
San Francisco County
3 ZIP codes
CA
San Mateo County
1 ZIP code
CA
Santa Barbara County
1 ZIP code
CA
Santa Clara County
4 ZIP codes
CA
Santa Cruz County
1 ZIP code
What zipradar surfaces at the California county level
County governments — not states or the federal government — own four of the most decision-relevant neighborhood-data layers. zipradar federates each from its authoritative public source, refreshed on the cadence each agency publishes.
- Property tax
- California county assessors publish parcel-level millage rates and assessed values. zipradar federates the county-by-county tax structure so a buyer can compare effective tax burden across California's 13 counties. Annual reassessment cadence; check each county for the most recent reassessment year.
- Deed activity
- County recorders log every property transfer. zipradar surfaces aggregated deed activity (count of recent transfers, median sale price ranges) at the ZIP level, never owner names or PII. Daily filings; published with a 1-2 day recorder lag.
- Radon zones
- The EPA Map of Radon Zones classifies every US county into Zone 1 (highest risk), Zone 2 (moderate), or Zone 3 (lowest). The 1993 baseline is overlaid with state-level radon survey data when published. zipradar shows the zone designation for each California county.
- Sex offender registry
- County and state registries are linked in real time via the National Sex Offender Public Website (NSOPW). zipradar deep-links to the official registry — never caches personal records — so privacy statutes are honored at the source.
Other California data layers
Eight more dimensions sit above the county level — water quality, flood zones, wildfire risk, air quality, crime, schools, lead pipes, and zoning. State-wide rollups for California live at /state/ca/. Per-ZIP detail lives on each individual /zip/[code] page.
For the full source list, refresh cadence, and limitations of every dataset, see methodology. For plain-language explainers on what each dimension actually measures, see learn.