California property tax reassessment after buying
California has a reviewed reassessment-on-sale rule. This page explains what the rule means for buyers and links to county examples.
Reviewed state rule
California Proposition 13 (BOE). Under this rule, purchase price generally becomes the starting assessed value, subject to the reviewed cap rules. For a $300,000 purchase at a 0.7% launch-county average effective rate, the rough first-year property-tax planning estimate is $2,100/yr.
Base-year assessed value generally increases by no more than 2% annually; exclusions and supplemental assessments are not modeled.
County examples
| County | Median home | Typical tax | Example purchase | Estimated tax after purchase |
|---|---|---|---|---|
| San Mateo County | $1,559,600 | $9,519/yr | $1,949,500 | $11,898/yr |
| Marin County | $1,507,300 | $10,001/yr | $1,884,125 | $12,501/yr |
| Santa Clara County | $1,490,600 | $10,001/yr | $1,863,250 | $12,501/yr |
| San Francisco County | $1,394,500 | $9,862/yr | $1,743,125 | $12,327/yr |
| Alameda County | $1,090,100 | $8,474/yr | $1,362,625 | $10,593/yr |
| Santa Cruz County | $1,027,500 | $6,538/yr | $1,284,375 | $8,172/yr |
| Orange County | $962,600 | $6,330/yr | $1,203,250 | $7,913/yr |
| Napa County | $869,500 | $5,995/yr | $1,086,875 | $7,494/yr |
| Contra Costa County | $866,800 | $7,156/yr | $1,083,500 | $8,945/yr |
| San Diego County | $854,700 | $5,774/yr | $1,068,375 | $7,218/yr |
| Los Angeles County | $834,200 | $5,675/yr | $1,042,750 | $7,094/yr |
| San Luis Obispo County | $824,700 | $5,636/yr | $1,030,875 | $7,045/yr |
Sources and limits
Confidence: Medium. The state reassessment rule is reviewed against an official source, but county bills still depend on parcel value, exemptions, local levies, and timing.
Data as of 2024-12-31.
Sources: California State Board of Equalization — Proposition 13; U.S. Census Bureau ACS county median tax and home-value tables.
Read the reassessment and property-tax methodology or browse California county property-tax estimates.
Disclaimer: Estimate for budgeting only — not a tax bill and not legal or tax advice. Verify with the county assessor and a licensed professional before making financial decisions.