Thinking about moving in Sonoma but worried your property taxes will jump? You are not alone. Many longtime homeowners hold back from upsizing, downsizing, or relocating because they do not want to lose a low assessed value. The good news is that California’s Prop 19 can help you transfer your property tax base when you move, often keeping your annual tax bill more manageable.
In this guide, you will learn who qualifies, how the transfer works, what timelines to watch, and practical steps to file in Sonoma County. You will also see examples for both downsizers and move-up buyers. Let’s dive in.
Prop 19 in a nutshell
Prop 19 updated California’s property tax rules for certain homeowners. It allows eligible owners to transfer the taxable value of a primary residence to a replacement primary residence in California. It also narrowed the rules for transferring low assessed values between parents and children.
The core idea is simple. If you qualify, you can move and carry a lower assessed value to your next home. That can reduce the property-tax impact of buying later in life or relocating after a disaster.
Who qualifies in Sonoma
You may be eligible to transfer your base-year value if any of the following apply:
- You are age 55 or older.
- You are a severely disabled homeowner.
- Your home was substantially damaged or destroyed in a wildfire or other declared disaster.
The home you sell must be your principal residence at the time of sale, and you must transfer the base value to another primary residence.
Where you can move and how often
Under Prop 19, you can transfer your base-year value to a replacement primary residence located anywhere in California. That includes moves within Sonoma County or between counties.
Prop 19 expanded transfer opportunities for homeowners who are 55+ or severely disabled compared with prior law. Disaster-related transfers have their own timing rules and may be treated differently. Because limits and procedures are administered at the county level, confirm current rules with the Sonoma County Assessor before you make plans.
Timing basics to know
Timing matters. The state allows transfers when the purchase or new construction of the replacement home occurs within a limited window before or after the sale of the original home. In many cases, homeowners can apply for transfers that occur up to two years before or after the sale. Always confirm your specific filing window with the Sonoma County Assessor, especially if you are coordinating a sale and purchase.
How the tax transfer is calculated
Prop 19 uses a simple framework to set the assessed value of your replacement home:
- If the replacement home’s market value is equal to or less than the original home’s sale price, your transferred taxable value generally stays the same.
- If the replacement home’s market value is higher, your transferred value increases by the difference.
Here is an illustrative example:
- Original home market value at sale: $800,000
- Original taxable value (assessed base): $200,000
- Replacement home purchase price: $1,200,000
- Upward adjustment: $1,200,000 minus $800,000 = $400,000
- New taxable value: $200,000 + $400,000 = $600,000
Your annual property tax is roughly 1 percent of assessed value plus any voter-approved local assessments. In this example, taxes would be based on about $600,000, not $1,200,000.
Why it matters for downsizers
If you plan to buy a less expensive home in Sonoma, Prop 19 can help preserve your lower assessed value. That can make it easier to move into a home that better fits your current lifestyle without a big property-tax increase.
Keep in mind that other costs are separate from property taxes. Your mortgage payment, HOA dues, insurance, and any local special assessments will still apply to your new home.
Why it matters for move-up buyers
If you are buying a more expensive home, Prop 19 still provides value. You carry your original base and add only the difference between the two market values. In many Sonoma neighborhoods, this can lead to a significantly lower assessed value than a full reassessment at the new purchase price.
This can be helpful if you are moving for space, a different lot, single-level living, or proximity to services, and you want to manage your ongoing property-tax costs.
Intergenerational transfers and planning
Prop 19 narrowed property tax exclusions for transfers between parents and children, and between grandparents and grandchildren. Today, keeping the prior assessed value is limited to certain transfers of a family home that becomes the child’s principal residence, subject to value limits and other conditions.
If you are considering gifting, inheriting, or estate planning with Sonoma property, speak with an estate-planning attorney and the Sonoma County Assessor. The rules can be nuanced and may affect your plans.
What Prop 19 does not change
Prop 19 affects your assessed value for property tax purposes. It does not change:
- Voter-approved special assessments or Mello-Roos bonds that may apply to a property.
- Federal income taxes or capital gains taxes. These are separate matters and should be reviewed with a tax professional.
Step-by-step: filing in Sonoma County
Use this checklist to keep your transfer on track. Because procedures can change, contact the Sonoma County Assessor early in your process.
- Confirm eligibility.
- Verify you meet one of the categories: 55+, severely disabled, or wildfire/disaster related displacement.
- Confirm the home you are selling was your principal residence.
- Call the assessor before escrow closes.
- Ask for the latest Prop 19 guidance, required claim form(s), and the current filing window.
- If you are moving to or from another county, ask about coordination steps between assessors.
- Gather documentation.
- Proof of age or disability if applicable.
- Deed and sale documents for your original home.
- Purchase agreement or new construction documents for your replacement home.
- Proof that each property is or will be your principal residence. Common examples include a driver’s license address, voter registration, or utility bills.
- File the claim on time.
- Complete and submit the county claim(s) within the specified window.
- Keep copies of everything you submit and any confirmations you receive.
- Save the final determination.
- Maintain the assessor’s approval and final assessed value for your records.
Sonoma scenarios to consider
- Downsizing near town services. If you sell a larger home and buy a lower-priced condo or single-level home closer to the Plaza, your transferred assessment can help keep taxes predictable while you reduce maintenance.
- Moving for yard space or an office. If you are upsizing from a townhouse to a single-family home with a yard, an upward adjustment may still leave you with a lower assessed value than a full reassessment.
- Rebuilding or replacing after a disaster. If your home was damaged or destroyed by wildfire or another declared disaster, special provisions and deadlines may apply. Contact the assessor as early as possible to review options and timing.
Common mistakes to avoid
- Waiting too long to file. Filing windows matter. Start with the assessor before you set closing dates.
- Assuming vacation or rental properties qualify. The transfer applies to primary residences only.
- Ignoring local assessments. Compare potential special assessments in your target neighborhood so you can budget accurately.
- Overlooking documentation. Keep clear proof of principal residence and your eligibility category ready.
Planning your move with confidence
Prop 19 can remove a major barrier to moving in Sonoma. Whether you are trading stairs for single-level living, seeking more outdoor space, or relocating closer to services, understanding how your assessed value can transfer empowers you to make a confident decision.
This guide is general information. Because Prop 19 is implemented by county assessors, always confirm your situation with the Sonoma County Assessor and consult a qualified tax advisor or attorney for legal and tax guidance.
If you want help timing your sale, comparing neighborhoods, or aligning your purchase with Prop 19’s rules, connect with a local expert who knows the Sonoma market and the moving parts of a coordinated sale and purchase. Reach out to Miranda Hanson for personalized guidance and a smooth, well-planned transition.
FAQs
Who qualifies for a Prop 19 base transfer in Sonoma?
- Homeowners who are 55 or older, severely disabled, or displaced by wildfire or another declared disaster, selling a principal residence and buying another primary residence in California.
Can I move anywhere in California and keep my assessed value?
- Yes. Prop 19 allows eligible homeowners to transfer a qualifying base-year value to a replacement primary residence located anywhere in California.
How is my new assessed value calculated if I buy a pricier home?
- Your original assessed value carries over and is increased by the difference between the replacement home’s market value and the original home’s sale price.
Will downsizing lower my property tax bill in Sonoma?
- If your replacement home’s market value is equal to or less than your original home’s sale price, your transferred taxable value generally remains the same, which can help keep taxes lower.
What did Prop 19 change about parent-to-child transfers?
- It narrowed the exclusion so a prior assessed value may be preserved only for certain transfers of a family home that becomes the child’s principal residence, and value limits apply.
What should I do first to use Prop 19 in Sonoma County?
- Contact the Sonoma County Assessor early to confirm eligibility, timelines, and required forms, then gather documentation and plan your sale and purchase around the filing window.
