Estimate your California property tax under Proposition 13, project 20 years at the 2% cap, and see your Prop 13 savings if you've owned for a while.
Estimate using county-level effective rates. Exact rates vary block by block with local bonds. For the binding figure use your county assessor with your APN.
California's property tax system is built around Proposition 13, passed in 1978. It has two famous protections — a 1% rate cap and a 2% annual growth cap on assessed value — and a less-famous third rule that ties everything together: assessed value resets to the price you pay when the property changes hands. That single rule is why long-time California owners pay so much less than new buyers on identical homes, and why most other state property-tax intuitions don't translate to California.
| County | Effective Rate | Median Home Value | Median Tax |
|---|---|---|---|
| Los Angeles | ~1.16% | $795,000 | ~$9,200 |
| Orange | ~1.05% | $925,000 | ~$9,700 |
| San Diego | ~1.08% | $765,000 | ~$8,300 |
| Santa Clara | ~1.16% | $1,450,000 | ~$16,800 |
| San Francisco | ~1.18% | $1,380,000 | ~$16,300 |
| Alameda | ~1.15% | $825,000 | ~$9,500 |
| Contra Costa | ~1.20% | $830,000 | ~$10,000 |
| Sacramento | ~1.12% | $555,000 | ~$6,200 |
Because assessed value only grows 2% a year, the gap between assessed and market value widens with every passing year of California's housing inflation. A $500,000 home bought 20 years ago has a 2026 Prop 13 assessed value around $743,000 regardless of market value. If that same home is now worth $1.5 million on the open market, the long-time owner pays ~$8,000/year while a new buyer of the identical property would pay ~$16,500 — a roughly $8,000/year Prop 13 dividend that lasts as long as you own.
Prop 19 (effective April 1, 2021) rewrote two important Prop 13 transfer rules:
When you buy in California, the county reassesses the property to your purchase price. The difference between the seller's old assessed value and your new one creates a one-time supplemental tax bill for the prorated remainder of the fiscal year — separate from the regular bill, usually not in your initial escrow, and arriving months after closing. New buyers should set aside cash for it.
Many newer California subdivisions sit in a Community Facilities District (CFD) that funds local infrastructure with a Mello-Roos special tax. It is billed on top of your Prop 13 rate, can add $1,000–$5,000+/year, and is NOT capped by the 2% rule. Ask for the exact amount before buying in a CFD.
If the home is your principal residence on January 1 and you file form BOE-266 once with the county assessor, your assessed value drops by $7,000 — saving ~$70–$90/year at typical effective rates. It auto-renews. Disabled veterans qualify for a much larger exemption.
If your home's market value falls below its Prop 13 assessed value (rare in recent years but common during downturns), file a Decline-in-Value (Prop 8) request. For formal disputes the Assessment Appeal Application window is typically July 2 – September 15 (county-specific). A successful Prop 8 reduction is temporary — when market recovers, the assessed value can rise back up to (but not above) the original factored Prop 13 value.