Fix California's unfair property taxes. Cut the rate to 0.7%, and apply it to everyone.
Why should your neighbor pay a tenth the property tax you do, just because they managed to buy a home in 1980? California taxes property based on its value when it was bought, not its value today. One Rate California is a revenue-neutral reform proposal: replace Prop 13's formula (property taxes go up 2% or inflation, whichever is lower) with consistent market-value assessments statewide, with a transitionary plan to prevent displacement, and cut the general property tax rate from 1% to 0.7%, approximately the rate that would keep overall property tax revenue unchanged.
Open source on GitHubAssessed value vs Market value
A random San Francisco home. Actual tax paid is real data from the SF Assessor's rolls since 2007 (the earliest digitized); market value is estimated from FRED's SF house price index.
The unfair status quo
We mapped the subsidy in SF, down to each single-family home, condo, and multi-family building. Prop 13 applies to commercial property too, but we focused on residential property.
Map © The Tax Fairness Project — open full interactive map ↗ (data reflects 2019–2020 county records and valuation estimates).
Drag to pan, scroll or double-click/pinch to zoom, click any home for its numbers. Zoom in (or pick a neighborhood above) to see its boundary and average subsidy. Map data © OpenStreetMap contributors.
Each neighborhood is shaded and labeled by its average subsidy, weighted per home — a 200-unit building counts as 200 homes, not one. Drag to pan, scroll to zoom. Map data © OpenStreetMap contributors.
Methodology
Assessed values come directly from the San Francisco Assessor-Recorder's official public dataset (DataSF: Assessor Historical Secured Property Tax Rolls). Since there's no open dataset of actual sale prices, current market value is estimated: for each home, we find nearby "comps" whose assessed value recently reset to a real market level, then apply their median price-per-square-foot to the home in question. A reset is confirmed by checking multiple years of each parcel's own assessment history — Prop 13 caps ordinary inflation adjustments at about 2% a year, so a jump larger than that, together with a recorded sale nearby, means an actual reassessment happened. This catches non-arms-length transfers (family and trust transfers, batch administrative recordings) that have a sale date on file but never reset to market value, and would otherwise distort the comps.
Checked against homes that themselves sold in 2024–2025 (so their true value is essentially known), this estimate lands within 20% of the real value about 71% of the time, with a median error of about 6%. It's least reliable at the very top of the market, where a simple nearby-comps approach undershoots distinctive, high-end properties — for that reason, an estimate is never allowed to fall below a home's own current assessed value, which otherwise showed up as an obviously-wrong "underwater" result for expensive homes with few comparable local sales. Treat every number here as a rough estimate, not an appraisal — county bond rates are held at San Francisco's ~0.18% for simplicity, and the same general tax rates used in the calculator above (1.00% today, 0.70% proposed) are applied throughout.
Multi-family buildings (larger, square markers) use a simpler, rougher method, since actual building sales are much less frequent: rather than nearest individual comps, every confirmed sale in a neighborhood is averaged into one $/sqft figure, applied to every building in that neighborhood. Neighborhoods with too few confirmed sales fall back to a $/sqft average pooled from their 5 nearest neighborhoods instead. This values the whole building at once, not individual units — the map's per-unit figures simply divide that building-level number evenly across units, which won't match any specific unit's real value. It says nothing about any tenant's actual rent, only about the building owner's assessed-vs-market tax gap.
Methodology
Each neighborhood's average is computed on a per-home basis, not a per-building basis: every multi-family unit is counted as its own home (weighted by unit count), so a 200-unit building contributes 200 data points, not one. The $ figure is each home's own estimated dollar subsidy (building subsidy divided evenly across units, for multi-family). The % figure is (estimated market value − assessed value) ÷ estimated market value — the assessment-gap discount as a share of true value. That ratio is independent of the tax rate itself, since the same rate multiplies both sides of the comparison.
Multi-family buildings with no reported unit count (a small share of buildings) are excluded from these per-home averages, since there's no way to know their true per-home split. See the "Individual homes" tab's methodology for how assessed and market values themselves are estimated.
Methodology
This map is an embed of The Tax Fairness Project's own Bay Area map, built from their own data and methodology (2019–2020 county records and valuation estimates) — not ours. See their site for details on how they estimate market values and subsidies. It covers the whole Bay Area, not just San Francisco, but on an older data vintage than our own SF-specific map in the other two tabs.
The proposal, in three parts
Assess consistently, at market value
Replace Prop 13's acquisition-value system — where a property's taxable value is frozen at its purchase price and can rise at most 2% a year — with regular assessment at current market value, applied the same way to every property.
Cut the general rate by about 30%
Lower the general property tax rate from 1.00% to 0.70%, so that statewide revenue stays approximately flat once the assessment base widens. This is a rate cut, not a new tax.
Preserve existing voter-approved bonds
Local bond and assessment rates that voters already approved to repay specific debts stay in place, unchanged, on top of the general rate — only as much as needed to service that existing debt.
How the increase is phased in
A lower rate and consistent assessment don't mean every affected bill changes overnight. Nobody should have to move out of a home they can otherwise afford just to cover the change.
The gap between assessed and market value doesn't just disappear in the meantime, though. Each year's shortfall accrues, and becomes payable when the home is next sold or transferred — including by inheritance. In effect, a longtime owner gets a capped, predictable annual increase for as long as they keep the home; the rest is settled at the point where the property's value question gets resolved anyway.
Calculator: what would this mean for your bill?
Enter numbers from your own property tax bill, look up any San Francisco address, or start with the pre-filled example. Every figure below is adjustable — nothing here is a hidden assumption. Two homes on the same block can have wildly different bills purely because of when they were bought — try looking up two nearby addresses to see it for yourself.
Your property
Assumptions (adjustable)
Held constant for simplicity; in reality it would likely fall some as the assessment base grows.
This implies a statewide assessment-base growth of about 42.9% relative to today, for the reform to stay revenue-neutral.
Today, under Prop 13
$0/yr
Under this reform
$0/yr
Illustrative estimates based on the numbers you enter — not tax advice or an official projection.
FAQ
Will my taxes go up?
It depends on how your current assessed value compares to today's market value — use the calculator above with your own numbers to see where you land. If you bought recently, or your assessed value is already close to market value, your bill would likely fall, since the general rate itself drops by about a third. If you've owned your home a long time in an area where prices have risen a lot, your assessed value is probably far below market value, and your bill would gradually rise to reflect that. See how the increase phases in above.
What about seniors on fixed incomes?
We want you to be able to stay in your homes! Under this plan, your annual bill can only rise 4% a year no matter how far below market your assessed value is, for as long as you keep the home. Nobody has to move, or find a lump sum, to cover the difference — the difference is deferred, not forgiven, and comes due at the next sale or transfer.
Is this a tax increase?
No. This is a revenue-neutral adjustment to the way property tax is calculated, so that it's applied equally by design, and is fairer to the neediest homeowners.
What happens to Prop 13's other protections?
Prop 13 bundles several distinct protections: it caps the general property tax rate at 1%, it freezes assessments at purchase price with at most a 2%-a-year increase, and it requires a two-thirds vote for certain new state taxes. This proposal touches only the first two, and only for the general rate and the acquisition-value assessment rule — it does not change the supermajority vote requirement for new taxes, and it does not, on its own, change transfer, exemption, or inheritance rules beyond what's needed to assess property consistently.
Join us
Californians for Fair Property Taxes is a new effort, started in 2026 — we're still building out the campaign.
This project was started by Barak, a San Francisco resident (and homeowner!) fed up with Prop 13. He donates his own Prop 13 tax break to YIMBY Law. Check out barakgila.com for more of his work.
This project has not received any external funding and is not yet incorporated; all donations (if any) will be made public.