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Castaic property taxes. A flat year. Recent buyers, look closely.

By Vulorean · Published October 4, 2026

The typical home in Castaic, in Los Angeles County, was worth about $804,000 in January 2026, 2.8% 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 Castaic home values did

Castaic values were essentially flat into January 2026, sitting 2.8% under the January 2025 high. Across Los Angeles County, the typical value was 1.6% below its own peak at the same point, so Castaic saw a deeper drop than the county as a whole.

Values kept falling after January: by August 2026 the typical home was 1.3% lower again. If that holds through January 1, 2027, next year's case could be stronger than this year's.

Which Castaic 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 $804,000.

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 $853,000 after the 2% annual increases, about $50,000 more than the January 2026 typical value. At California's 1% base tax rate, that's on the order of $500 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.

Los Angeles 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 Los Angeles 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 Castaic owners file

Castaic assessments are set by the Los Angeles 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 Los Angeles County guide lists step-by-step instructions and official links.

Building a Castaic case

Market averages explain why an appeal might work. The board decides on evidence about one property. Look for sales of similar homes in Castaic 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.

Smaller communities can have few sales in any month. If nearby Castaic sales are thin, widen the search area before you widen the date range, and explain why each sale still compares.

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.