California Property Tax Calculator

California property tax begins with Proposition 13, approved by voters in 1978. Prop 13 sets the general levy at 1% of assessed value and fixes that assessed value at the purchase price in the year the property changes hands — the "base year value." From there, the assessor may increase assessed value by no more than 2% per year, even if market values climb far faster. That is why two identical homes on the same street can carry very different tax bills: the one bought decades ago is still assessed near its old price.

The 1% general levy is only part of the bill. Each county layers on voter-approved bond rates for schools, community colleges, water districts, and local measures. Those additions are what move the effective rate to roughly 1.09% in Orange and San Mateo counties and up toward 1.24% in Santa Clara County. Two properties in the same county can also differ, because bond rates apply by district rather than county-wide.

Mello-Roos special taxes are levied inside Community Facilities Districts, which cities and counties form to finance the infrastructure a new subdivision needs — schools, roads, parks, sewers. Because of that, Mello-Roos shows up most often on master-planned and newer-construction neighborhoods in Riverside, San Bernardino, Placer, and San Joaquin counties. It is a flat annual charge rather than a rate, and $1,500 to $5,000 a year is common. A separate 1915 Bond assessment can also apply where specific street, sewer, or utility improvements were financed.

Neither charge is visible in a listing price, and neither is captured by a rate-only estimate — which is why California sellers disclose them. A Natural Hazard Disclosure report from Verity NHD researches the parcel's actual tax record and discloses Mello-Roos, 1915 Bond, and other special assessments alongside the statutory hazard determinations, so buyers see the real carrying cost before contingencies are removed. You can review what an NHD report costs or compare providers side by side.