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Contra Costa County · San RamonSan Ramon property taxes. A softer market. A higher bill?
In January 2026, the typical home in San Ramon, in Contra Costa County, was worth about $1,489,000. That's 11.8% below the June 2022 peak of $1,688,000. California assessments don't always fall when the market does, so some San Ramon owners may be taxed on a value the market no longer supports.
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What San Ramon home values did
San Ramon values peaked in June 2022, then slid 11.8% by January 2026, the month that matters for the 2026 assessment. Across Contra Costa County, the typical value was 11.7% below its own peak at the same point, so San Ramon saw about the same drop as the county as a whole.
Values kept falling after January: by August 2026 the typical home was 2.5% lower again. If that holds through January 1, 2027, next year's case could be stronger than this year's.
| Measure | Value |
|---|---|
| January 2026 (2026 lien date month) | $1,489,000 |
| Peak since 2021 | $1,688,000 in June 2022 |
| January 2026 vs. peak | -11.8% |
| January 2026 vs. January 2025 | -7.3% |
| Latest (August 2026) | $1,451,000 |
Which San Ramon owners may be over-assessed
Under Prop 13, your assessment starts at your purchase price and can rise up to 2% a year. Under Prop 8, it must drop to market value whenever market value as of January 1 is lower. The table compares a typical purchase in each year with the January 2026 typical value of $1,489,000.
| Bought in | Typical price that year | Rough 2026 assessment | vs. January 2026 value |
|---|---|---|---|
| 2021 | $1,275,000 | $1,408,000 | Below market |
| 2022 | $1,577,000 | $1,707,000 | Possibly over-assessed by about $219,000 |
| 2023 | $1,478,000 | $1,568,000 | Possibly over-assessed by about $80,000 |
| 2024 | $1,584,000 | $1,648,000 | Possibly over-assessed by about $159,000 |
| 2025 | $1,542,000 | $1,573,000 | Possibly over-assessed by about $85,000 |
The buyers most likely to be over-assessed are those who bought in 2022, 2023, 2024 and 2025. A typical 2022 purchase would carry a 2026 assessment of roughly $1,707,000 after the 2% annual increases, about $219,000 more than the January 2026 typical value. At California's 1% base tax rate, that's on the order of $2,190 a year before local voter-approved add-ons.
This is an illustration built on citywide typical values, not an estimate of your home. Your assessment notice shows your actual assessed value, and some assessors lower values on their own in a falling market, so check it first. If you do appeal, your evidence has to show your home's market value.
Contra Costa County deadlines
- 2026 regular filing period: July 2 through November 30, 2026. If you think the 2026 value is too high, this is the window.
- Informal review: the Contra Costa County Assessor may review a decline-in-value request informally. File the formal application anyway if the deadline is close; an informal review doesn't extend it.
- Supplemental or escape assessments: these have their own deadline, generally 60 days from the notice date. Check the notice.
Where San Ramon owners file
San Ramon assessments are set by the Contra Costa County Assessor. Formal appeals go to the county's assessment appeals board, not to the city.
| Form | BOE-305-AH, the state Assessment Appeal Application |
|---|---|
| Filing deadline | November 30 (regular window) |
| Where to file | Contra Costa County Clerk of the Board (assessment appeals) |
| Assessor | co.contra-costa.ca.us · 925-313-7400 |
Confirm the current form, fee and address with the county before you file. The Contra Costa County guide lists step-by-step instructions and official links.
Building a San Ramon case
Market averages explain why an appeal might work. The board decides on evidence about one property. Look for sales of similar homes in San Ramon that closed near January 1, 2026. The BOE treats comparable sales as the strongest evidence for a home, and the appeals board can't consider sales more than 90 days after the valuation date. Match living area, age, condition, lot and location as closely as you can, and write down every difference you can't adjust for.
San Ramon sits in the San Francisco-Oakland-Berkeley metro, but neighborhood differences matter more than metro trends. A sale across town can be a weaker comparison than one a few streets away.
A Vulorean report pulls comparable sales and a January 1 value opinion into one document you can file with. Eligible self-file reports are free during launch, with no payment card required. Review every comparison before you use it; you know your home's condition better than any dataset.
Check your San Ramon property for free
Start with your address. Eligible self-file reports are free during launch; an account and available report allowance are required. County filing fees are separate.
Start my free property check →Home values: Zillow Home Value Index (ZHVI), all homes, mid-tier, smoothed and seasonally adjusted, through August 2026, from Zillow Research. Purchase-year rows use each year's average typical value and assume the maximum 2% annual increase. Deadlines: California BOE county filing periods. Vulorean is an independent service, not a government office.