How to Lower Property Taxes in California
California's property tax system works differently from most states — thanks to Proposition 13, your assessed value is generally capped at 2% growth per year once you buy. That cap is a protection, but it doesn't prevent over-assessment at purchase or after certain events like new construction or a change in ownership. If your assessed value is higher than your home's current market value, you can file an appeal with your county's Assessment Appeals Board/AAB — and you can do it yourself, for free.
Is Your California Assessment Too High?
California assesses property at its full cash value at the time of purchase, then limits annual increases. The county assessor can also reassess upward after new construction or a change of ownership — these are the moments where errors most often creep in. Start by pulling your property's current assessed value from your county Assessor's Office website and comparing it to recent nearby sales. If comparable properties sold for meaningfully less than your assessed value, that gap is your appeal argument. Also check your property record for factual errors: wrong square footage, miscounted bathrooms, or a bedroom in unfinished space. To appeal, download the Application for Changed Assessment from your county AAB's website and file by November 30 (confirm the exact window with your county AAB). Bring three to five comparable sales and any photos or repair estimates documenting condition issues. Hearings before the three-member Assessment Appeals Board are informal — present your evidence, stay concise, and focus on the comps. If the board rules in your favor, the reduction applies to the tax year in question.
Exemptions: A Faster Way to Reduce Your Bill
An appeal challenges your assessed value; exemptions reduce the taxable portion directly, no hearing required. California offers several worth checking before or alongside an appeal:
- Homeowners' Exemption — reduces assessed value by a set amount for your primary residence. Apply once through your county assessor.
- Disabled Veterans' Exemption — a larger reduction for qualifying veterans; income limits may apply.
- Proposition 19 transfers — if you're 55 or older, severely disabled, or a disaster victim, you may be able to transfer your existing low assessed value to a replacement home in California. Check eligibility with your county assessor.
Verify current eligibility and deadlines with your county assessor — exemption rules vary and change.
DIY vs. Hiring a Tax Agent
California allows licensed tax agents and attorneys to represent you before the AAB, typically on contingency — a percentage of first-year savings if they win, nothing if they don't. For a straightforward overvaluation with solid comparable sales, the DIY route is very achievable. Professional help makes more sense for high-value or complex properties.
California Assessments Do Not Follow the Market — Which Changes What an Appeal Is
California has an effective rate of 0.71%, ranking 35 of 51 states and the District of Columbia — below the middle. Yet the median household pays $4,926 a year, more than in most high-rate states, because the median home is valued at $695,400. The rate is modest; the base is not.
More importantly, California assessments work differently from almost everywhere else, and that determines what you can actually appeal. Under Proposition 13 your assessment is not a current estimate of market value. It is a base year value, set when you bought the property or completed new construction, and then increased each year by the California Consumer Price Index — capped at a maximum of 2% per year. Absent a change in ownership or new construction, the assessed value can never rise above that factored base year value.
The Appeal That Actually Applies: Decline in Value Under Proposition 8
Because your assessment trails the market by design, arguing that your home is worth less than a neighbour's is usually beside the point. The question California asks is narrower: has market value fallen below your factored base year value? If it has, Proposition 8 allows a temporary reduction to that lower market value, reviewed each year. When the market recovers, the assessment returns toward the base year value — the reduction is not permanent and does not reset your base.
The valuation date is fixed: January 1 of the year you file, the lien date. Evidence about what happened in March is irrelevant to a January 1 value. Sales closest to that date carry the weight.
| Element | Rule |
|---|---|
| Annual increase limit on assessed value | California CPI, maximum 2% |
| Valuation date for a decline-in-value appeal | January 1 (lien date) |
| Filing period, counties mailing notices to all owners by August 1 | July 2 – September 15 |
| Filing period, counties that do not | July 2 – November 30 |
| Who carries the burden of proof on an owner-occupied single-family home | The Assessor |
The burden of proof point is the one most owners never hear. In an appeal concerning an owner-occupied single-family dwelling that is your principal residence, the Assessor — not you — bears the burden of proof and must present evidence first to justify the assessment. The same applies where the Assessor enrolled a value different from your purchase price and you filed a Change in Ownership Statement on time. In all other situations the burden is yours. For a homeowner appealing their own home, this reverses the usual posture of a hearing.
Each of California's 58 counties sets its own filing period by April 1 and publishes it locally, so confirm yours rather than assuming September 15. Both windows open on July 2.
Median Tax by California County
The eight counties with the highest median bills, of 58. Note how little the effective rate varies next to the spread in home values — that is Proposition 13 at work.
| County | Median tax paid | Median home value | Effective rate |
|---|---|---|---|
| Marin | $10,001+ | $1,390,000 | 0.72% |
| Santa Clara | $9,766 | $1,382,800 | 0.71% |
| San Francisco | $9,412 | $1,380,500 | 0.68% |
| San Mateo | $9,167 | $1,494,500 | 0.61% |
| Alameda | $8,061 | $1,057,400 | 0.76% |
| Contra Costa | $6,903 | $830,800 | 0.83% |
| Santa Cruz | $6,305 | $1,015,200 | 0.62% |
| Orange | $6,096 | $915,500 | 0.67% |
About the figures marked with a plus. The Census Bureau caps its median tax estimate at $10,001, which stands for "$10,000 or more". Where that figure appears, the true median is higher and the effective rate shown is correspondingly understated.
Source for the tax and value figures. U.S. Census Bureau, American Community Survey 2019–2023 five-year estimates, tables B25103 (median real estate taxes paid) and B25077 (median value), owner-occupied housing units. The effective rate is median tax divided by median value.
California Appeals: What Owners Ask
Why can my assessment be far below my neighbour's for an identical house?
Because Proposition 13 bases each assessment on the year the property last changed hands, then limits annual growth to the California CPI up to 2%. Two identical homes bought fifteen years apart carry very different assessments by design. That difference is lawful and is not grounds for an appeal.
So what can I appeal?
Primarily a decline in value under Proposition 8 — that market value as of January 1 has fallen below your factored base year value. You can also contest a newly established base year value after a purchase or construction, and an escape assessment. What you cannot do is appeal because someone else is assessed lower.
Does a Proposition 8 reduction stay?
No, and that distinguishes California from states like Georgia or New Jersey where a reduction is held for following years. A Proposition 8 reduction is temporary and reviewed annually; as market value recovers the assessment climbs back toward the factored base year value. Your base year value itself is unaffected.
When exactly can I file?
The window opens July 2 everywhere. It closes September 15 in counties where the Assessor elects to mail assessment notices to all property owners by August 1, and November 30 in counties that do not. Each county fixes and publishes its period by April 1.
Do I need an appraisal?
Not necessarily, and for an owner-occupied home the burden sits with the Assessor in the first place. Comparable sales close to January 1 are usually sufficient. A paid appraisal becomes worth considering where the property is unusual or the amount in dispute is large.
What value date do I need evidence for?
January 1 of the year you file — the lien date. Sales after that date are of limited use, which is why a falling market late in the year does not help the current appeal but may support next year's.
Sources for the procedure. California State Board of Equalization, Residential Property Assessment Appeals (Publication 30, February 2020): base year value and the CPI-linked 2% annual limit, decline-in-value appeals under Proposition 8 and the January 1 lien date as valuation date, the July 2 – September 15 and July 2 – November 30 filing periods and how a county's period is determined, and the burden of proof rules including owner-occupied single-family dwellings.