Under Prop 19, a California homeowner 55 or older may transfer their factored base year value up to three times to a replacement primary residence anywhere in the state, including across the Ventura and Los Angeles County line. A Thousand Oaks seller with a $310,000 factored base who sells for $1,150,000 and buys a $1,400,000 Westlake Village home carries a new assessed value of $560,000, not $1,400,000, saving roughly $9,200 per year in property taxes. Claims are filed on form BOE-19-B with the assessor where the replacement home sits, within three years of purchase for full retroactive relief.
Key Takeaways
- Under Prop 19, California homeowners 55 or older can transfer their factored base year value to a replacement home up to three times, anywhere in the state, including across county lines.
- Claims must be filed on form BOE-19-B with the assessor where the replacement home is located, within three years of purchase, for full retroactive relief.
- A replacement home purchased above the original sale price still qualifies; only the difference between the two prices is added to the transferred taxable value.
- A Thousand Oaks seller with a $310,000 factored base who sells for $1,150,000 and buys a $1,400,000 Westlake Village home gets a new assessed value of $560,000, saving about $9,240 in year one.
- Westlake Village had a median sale price of $1,634,182 as of July 2026, up 16.1% year over year, according to Redfin.
Last updated: August 2026.
If you bought on Lang Ranch Parkway in 1996 or off Lindero Canyon Road in 1999, your property tax bill is probably the single best financial deal you own. That is exactly why so many Conejo Valley homeowners stay in a two story, five bedroom house they no longer need. The Prop 19 property tax transfer California created in 2020 removes that trap: your low assessed value moves with you. With the median Westlake Village sale price at $1,634,182 as of July 2026, up 16.1% year over year according to Redfin, the difference between a transferred tax base and a fresh reassessment is now worth six figures over a decade.
What is the Prop 19 property tax transfer and who qualifies in the Conejo Valley?
Proposition 19 took effect April 1, 2021. It lets homeowners who are 55 or older, severely and permanently disabled, or victims of a wildfire or declared disaster transfer the taxable value of their principal residence to a replacement property up to three times, anywhere in the state, per the California State Board of Equalization. Taxable value means your base year value plus the annual inflation adjustments capped at 2%, known as your factored base year value.
Four qualifying conditions apply in both Ventura and Los Angeles counties. You or your spouse must be at least 55 at the time the original home sells. Both the original and the replacement must be your primary residence, with the homeowners' exemption claimed on each. The replacement must be purchased or newly built within two years of the sale, before or after. And the claim must be filed with the correct assessor.
Median Sale Price by Conejo Valley Community, Mid 2026
$0$500K$1M$1.5M$2M$1.63M$1.40M$1.20M$1.05MWestlake VlgAgoura HillsOak ParkThousand OaksRedfin median sale price (Westlake Village, Agoura Hills, Oak Park); Zillow home value index (Thousand Oaks)
Sources: Redfin city market pages and Zillow Home Value Index, July 2026
Does Ventura County allow intercounty transfers, and can I cross into Los Angeles County?
Yes. This is the question I answer most often at kitchen tables off Hampshire Road, because the old rules confused everyone. Before 2021, Propositions 60 and 90 required the replacement home to be equal or lesser in value and located in one of ten participating counties. Prop 19 replaced that. The Los Angeles County Assessor confirms the replacement residence can be of any value and anywhere within the state, and the Ventura County Assessor administers the same statewide rule.
That matters here more than almost anywhere in California, because the county line runs straight through the Conejo Valley. Westlake Village is split: the incorporated city sits in Los Angeles County, while the 91361 neighborhoods on the Ventura side are assessed in Ventura County. Sell in Thousand Oaks and buy in Calabasas, Hidden Hills, or Agoura Hills and your base year value still travels. It is worth understanding how the two county tax rolls differ on bond measures and direct assessments before you choose a side of the line, since the transferred base is identical but the rate applied to it is not. If your move stays local, the mechanics of relocating entirely within Ventura County are slightly simpler, because one assessor handles both sides of the transaction.
What if my new home costs more than my Thousand Oaks sale?
You still qualify. Prop 19 removed the equal or lesser value ceiling and replaced it with an upward adjustment. The Board of Equalization states there is no limit on the market value of the replacement property, but the amount in excess of the original property's market value is added to the transferred value.
The formula is simple arithmetic: new taxable value equals your factored base year value plus the difference between the replacement purchase price and the original sale price. Here is a real world Conejo Valley scenario, a single story trade from Thousand Oaks into Westlake Village.
| Line item | Amount |
|---|---|
| Original Thousand Oaks home, purchased 1996 | $285,000 |
| Factored base year value in 2026 (2% annual cap) | $310,000 |
| 2026 sale price | $1,150,000 |
| Replacement Westlake Village purchase price | $1,400,000 |
| Upward adjustment ($1,400,000 minus $1,150,000) | $250,000 |
| New transferred taxable value | $560,000 |
| Annual tax with Prop 19 transfer (approx. 1.10% Ventura County) | $6,160 |
| Annual tax if fully reassessed at $1,400,000 | $15,400 |
| Annual tax if reassessed in LA County (approx. 1.16%) | $16,240 |
| First year savings with the transfer | $9,240 |
| Ten year savings, assuming 2% annual growth on both bases | $101,000+ |
Combined rates vary by tax rate area because of voter approved bonds and direct assessments, so confirm your exact rate on your assessor bill. The pattern holds regardless: the upward adjustment taxes only the step up in purchase power, never the whole replacement home. Sellers weighing this math should also model the capital gains exposure that comes with a thirty year hold, because property tax relief and federal gain are two separate calculations.
Annual Property Tax on a $1,400,000 Westlake Village Replacement Home
$0$5K$10K$15K$20K$6,160$15,400$16,240Prop 19 transferReassessed, VenturaReassessed, LA CountyTransferred base $560,000Full market reassessment
Source: DB Real Estate Group calculation using Board of Equalization Prop 19 rules and typical combined county tax rates, 2026
How many times can I use Prop 19, and what are the deadlines?
Three times per qualifying person for age 55 and older or severely disabled claimants. Disaster and wildfire victims face no limit on the number of transfers. A married couple counts as one claimant unit, so three lifetime uses total, not three each.
Two clocks control the outcome. First, the two year window: the replacement must be purchased or newly constructed within two years before or after the sale of the original. Buy first and you will pay the full reassessed bill on the replacement until your original home closes, then receive a refund of the overpayment once the claim is approved. Second, the three year filing window: file within three years of the purchase or completion of construction and relief is retroactive to the qualifying date. File later and relief generally begins prospectively with the assessment year in which you file, which is money you never get back.
How do I file Prop 19 with the Ventura County or LA County Assessor?
- Confirm eligibility before listing. Verify your age on the sale date, your homeowners' exemption status, and whether you have used a base year transfer previously.
- Pull your current factored base year value. It appears on your annual bill or on the Ventura County Assessor and Los Angeles County Assessor parcel lookup tools. This number, not your purchase price, is what transfers.
- Sequence the two closings inside 24 months. Coordinate escrow dates deliberately; this is where a disciplined listing strategy in Westlake Village protects the tax benefit, not just the sale price.
- Record the deed and claim your homeowners' exemption on the replacement within the statutory window, filed alongside the transfer claim.
- File form BOE-19-B (Claim of Persons at Least 55 Years of Age for Transfer of Base Year Value to Replacement Primary Residence) with the assessor in the county where the replacement home is located, meaning Ventura County for Thousand Oaks, Newbury Park, or the 91361 side of Westlake Village, and Los Angeles County for Calabasas, Agoura Hills, Oak Park, or Hidden Hills.
- For a cross county move, expect form BOE-19-C, the certification of value completed by the assessor of the original property's county and routed to the new county.
- Attach proof and track the refund. Include both closing statements, proof of age, and occupancy documentation, then verify the corrected bill on your next annual notice.
Where are Conejo Valley downsizers actually buying in 2026?
Single level and gated inventory drives nearly every 55+ move I handle. In Oak Park, Redfin reports a $1.2 million median sale price with homes averaging 39 days on market, and the one story tracts near Medea Creek move fastest. Agoura Hills posted a $1.4 million median, up 11.0% year over year with 44 days on market. Thousand Oaks remains the value entry point, with a Zillow home value index of $1,047,273 and homes going pending in roughly 19 days, which means pricing a Thousand Oaks listing correctly in the first ten days is the difference between one offer and four.
Lifestyle drives the short list as much as the tax math. Buyers trading out of North Ranch want walkability to the lake and dinner within ten minutes, whether that is Mastro's Steakhouse on Westlake Boulevard or a Sunday morning at the Thousand Oaks farmers market. Buyers from Lang Ranch and Wildwood usually want to stay near the trailheads at Wildwood Regional Park, where the Paradise Falls loop is still the most used amenity in the Conejo Recreation and Park District system. Lake Sherwood and the gated pockets off Potrero Road attract the 3,000 square foot single level buyer who wants a lock and leave. One practical caution: new hillside purchases in Lake Sherwood, Hidden Valley, and upper Newbury Park frequently carry brush clearance requirements that affect coverage, so line up a homeowners insurance quote before you remove contingencies.
Frequently Asked Questions About Prop 19 in the Conejo Valley
Can I transfer my property tax base from Thousand Oaks to a home in Los Angeles County?
Yes. Prop 19 made base year value transfers statewide as of April 1, 2021, so a Thousand Oaks seller in Ventura County can buy in Calabasas, Agoura Hills, Oak Park, or Hidden Hills in Los Angeles County and carry the factored base year value. File BOE-19-B with the Los Angeles County Assessor, since the claim always goes to the county where the replacement home sits.
Does my spouse also get three Prop 19 transfers?
No. Spouses are treated as a single claimant unit, so a married couple shares three lifetime transfers, not six. Only one spouse needs to be 55 or older on the date the original primary residence sells.
What happens if I buy the replacement home before I sell my current one?
That is allowed as long as the sale closes within two years of the purchase. You will pay the fully reassessed bill on the replacement in the interim, and after the claim is approved the assessor issues a corrected assessment retroactive to the later of the two qualifying dates, with a refund for the overpaid period.
Does Prop 19 apply to a vacation home, rental, or Lake Sherwood second residence?
No. Both the original and the replacement must be your primary residence with the homeowners' exemption or disabled veterans' exemption in place. A Lake Sherwood second home, a rental in Simi Valley, or a Camarillo investment property does not qualify, though the underlying purchase math still favors buyers who understand how Conejo Valley rental returns pencil out.
Get Your Free Prop 19 Conejo Valley Downsizing Analysis
Enter your current address and your target price range, and Davis Bartels returns a one page PDF showing your estimated current home value, your transferred tax bill compared with a fully reassessed one, and three matching Westlake Village, Oak Park, or Lake Sherwood single level or gated options currently available.
About the author: Davis Bartels is a licensed California real estate broker based in Westlake Village and the leader of DB Real Estate Group, a top 1% nationally ranked team affiliated with Pinnacle Estate Properties. Since starting in the 2008 short sale market, he has closed more than 500 transactions and nearly $500 million in career sales volume, including a career best 100 closings and more than $103 million in 2025. He serves Westlake Village, Thousand Oaks, Newbury Park, Oak Park, Agoura Hills, Calabasas, Hidden Hills, Lake Sherwood, North Ranch, Lang Ranch, Dos Vientos, Wildwood, Simi Valley, Moorpark, Camarillo, Sherman Oaks, and Encino. License status is verifiable through the California Department of Real Estate. This article is educational and is not tax or legal advice; confirm your specific situation with the Ventura County Assessor or a qualified tax professional.
Thinking About Buying or Selling in Westlake Village / Thousand Oaks (Conejo Valley), with Ventura County & LA County assessor specifics?
Davis Bartels and the DB Real Estate Group have served families across the Conejo Valley and Ventura County since 2009, with 500+ closed transactions and nearly $500 million in career sales volume, including a career-best 100 closings and $103M+ in 2025. Whether you're exploring your options or ready to make a move, reach out for a no pressure conversation about your goals.
Contact Davis: davisbartels.com or (805) 341-6125
