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Sunnyvale property taxes. Prices stalled. Assessments kept climbing.

By Vulorean · Published October 4, 2026

The typical home in Sunnyvale, in Santa Clara County, was worth about $2,058,000 in January 2026, 0.3% less than a year earlier. Assessed values can still rise up to 2% a year, so a flat market can quietly push an assessment above what a home would sell for.

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What Sunnyvale home values did

Sunnyvale values were essentially flat into January 2026, sitting 0.3% under the January 2025 high. Across Santa Clara County, the typical value was 1.6% below its own peak at the same point, so Sunnyvale saw a smaller drop than the county as a whole.

Values kept falling after January: by August 2026 the typical home was 3.0% lower again. If that holds through January 1, 2027, next year's case could be stronger than this year's.

Which Sunnyvale 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 $2,058,000.

At the typical price level, no purchase year since 2021 shows a 2026 assessment above January 2026 market value. That doesn't rule out your home. A purchase above the typical price, a home that needs work, or an assessment that includes improvements you didn't get credit for can all create a gap that a citywide index can't see.

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.

Santa Clara County deadlines

• 2026 regular filing period: closed September 15, 2026. Santa Clara County uses the earlier California window.
• Next regular filing period: July 2 through September 15, 2027, for the 2027 roll.
• Before then: ask the Santa Clara County Assessor how and when it accepts informal decline-in-value review requests for 2027. An informal review never extends the formal deadline.
• Supplemental or escape assessments: these have their own deadline, generally 60 days from the notice date. Check the notice.

Where Sunnyvale owners file

Sunnyvale assessments are set by the Santa Clara County Assessor. Formal appeals go to the county's assessment appeals board, not to the city.

Confirm the current form, fee and address with the county before you file. The Santa Clara County guide lists step-by-step instructions and official links.

Building a Sunnyvale case

A citywide index shows the trend. Your appeal needs your house. Look for sales of similar homes in Sunnyvale 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.

Sunnyvale sits in the San Jose-Sunnyvale-Santa Clara 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.

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.