Did you just close on a home in Torrey Highlands and get a surprise “second” property tax bill in the mail? You are not alone. Many San Diego buyers are caught off guard by California’s supplemental property tax after a purchase. It is a normal part of the process, but it can be confusing the first time you see it.
In this guide, you will learn what triggers a supplemental assessment, how San Diego County calculates the amount, when bills arrive, your appeal options, and how to budget for it in Torrey Highlands. You will also get practical steps to avoid surprises. Let’s dive in.
What a supplemental tax is
A supplemental property tax is an additional bill that reflects the change in your home’s assessed value after a sale or new construction. Under California’s Prop 13 rules, the county reassesses your property at current market value when you buy. The supplemental bill captures the difference between your new value and the prior assessed value for the remainder of the fiscal year.
What triggers it
- A sale or change of ownership, which is what happens at closing.
- Completion of new construction or a major addition.
- Other changes that increase assessed value recorded by the Assessor.
Why you received a second bill
Your regular secured property tax bill still covers the full fiscal year based on the prior owner’s assessed value. The supplemental bill is separate. It covers only the portion of the fiscal year after your purchase date, based on the increase from the old value to your new assessed value. That is why it feels like a second bill. They cover different time periods.
How San Diego calculates your supplemental bill
The simple formula
- Prior assessed value
- New assessed value at your change-of-ownership date
- Increase equals new value minus prior value
- Multiply that increase by the combined tax rate
- Prorate for the days remaining in the fiscal year after your closing
Result: your supplemental tax amount for that partial year.
San Diego’s combined tax rate starts with the statewide 1.00 percent base. Many parcels also include voter-approved bonds, special assessments, and sometimes Mello-Roos or other community facilities district charges. Your exact rate depends on your parcel’s obligations.
Timing and proration
California’s fiscal year runs July 1 through June 30. If you close midyear, the county calculates tax on the value increase for the days left until June 30. The next regular secured bill will then reflect the full-year taxes on your new base value.
Counties sometimes issue more than one supplemental notice if values change or new information arrives. If you get multiple letters, review each carefully.
Tax rate factors in Torrey Highlands
Torrey Highlands includes newer planned neighborhoods where some parcels carry Mello-Roos obligations. These community facilities district charges increase your effective tax rate, which also increases the supplemental amount. Local bond measures and parcel taxes tied to your school and services districts may also apply. Parcel-level levies vary by address, so confirm details through San Diego County’s Assessor and Treasurer resources or with your escrow officer.
Who gets billed and who pays
San Diego County issues the supplemental bill to the owner of record at the time the assessment is made. After a purchase, that is usually you. Whether you or the seller pays in practical terms depends on your purchase agreement and escrow prorations. Many contracts address regular property tax prorations, not supplemental bills, unless you negotiated it. If your agreement allocates responsibility, escrow can reflect that with credits or reimbursements. Always check your executed contract and closing statement.
Timelines, payments, and appeals
Billing and due dates
Supplemental bills arrive separately from the regular secured bill and have their own due dates and penalties. If you miss the due date, standard property tax delinquency penalties and interest can apply. Watch your mail after closing, and set reminders to avoid late fees. For current payment deadlines, use the San Diego County Treasurer–Tax Collector guidance.
How to appeal a value
If you believe the supplemental assessed value is too high, you can file an assessment appeal with the County Assessment Appeals Board. Supplemental assessments have a shorter filing window. You typically have 60 days from the mailing date on the supplemental notice, or the standard July 2 to September 15 window for that fiscal year, whichever is later. Confirm the exact dates with the County Clerk of the Assessment Appeals Board.
Bring evidence such as your purchase contract, an independent appraisal, comparable sales, inspection reports, and any documentation that supports a lower market value as of your purchase date. If your appeal is successful, the county will reduce the assessment and issue a refund of any overpaid supplemental taxes as allowed.
Common reasons to appeal
- The sales price is not representative of market value, such as a distress or non-arm’s-length sale.
- Property characteristics are incorrect, for example an overstated square footage.
- The effective change date is wrong or there appears to be a duplicate assessment.
Torrey Highlands buyer tips
Budget smart before and after closing
- Ask escrow for an estimate. Before closing, request the seller’s prior assessed value and a rough calculation of your supplemental exposure based on your purchase price.
- Check parcel levies. Use county parcel tools or escrow documents to identify bonds, special assessments, and any Mello-Roos that apply to your address. These items increase your effective tax rate and your supplemental bill.
- Build a reserve. Set aside at least one month’s mortgage payment plus an additional 0.5 percent to 1.5 percent of your purchase price for taxes and assessments until all county bills arrive. If your parcel has higher Mello-Roos, increase your reserve.
- Review your closing statement. Look for any credits or concessions that cover regular property tax prorations or anticipated supplemental exposure.
- Plan for your escrowed mortgage account. Mortgage servicers do not always handle supplemental bills automatically. If you want them to, contact your servicer to request support or to adjust monthly escrow contributions.
- Track appeal deadlines. If you want to challenge the value, do not wait. The supplemental appeal timeline is short.
Quick examples
- Smaller increase case: If your purchase price is close to the prior assessed value, your supplemental bill for the remaining months of the fiscal year may be a few hundred dollars.
- Larger increase case: If the prior owner had a low base value and your purchase price is much higher, your supplemental tax could reach several thousand dollars even when prorated. Mello-Roos and parcel taxes can raise the total.
Step-by-step checklist
- Confirm the prior assessed value and your new assessed value after closing.
- Identify your parcel’s combined tax rate, including any bonds, special assessments, and Mello-Roos.
- Estimate the supplemental amount by applying the rate to the value increase, then prorating for the days remaining in the fiscal year.
- Watch your mail for the supplemental bill and assessment notice. Set a calendar reminder for the due date.
- Decide whether to pay directly or coordinate through your mortgage servicer.
- If needed, prepare an appeal package with comps, the purchase contract, and any appraisal.
- Keep copies of everything and verify any refunds if an appeal is granted.
Final thoughts for Torrey Highlands homeowners
Supplemental property tax is a normal part of buying in California, and it is especially relevant in communities with newer development patterns like Torrey Highlands. A little planning goes a long way. If you estimate the amount early, confirm your parcel’s levies, and watch the deadlines, you can avoid surprises and budget with confidence.
If you want a local perspective on how supplemental taxes fit into your overall monthly costs, or you need help reviewing parcel-level levies before you buy, our team is here to help. Reach out to Butler Group Real Estate for clear guidance tailored to North County buyers and sellers.
FAQs
What is a supplemental property tax bill in San Diego County?
- It is an additional bill that covers the tax on the increase in assessed value after your purchase or new construction for the remaining portion of the fiscal year.
Why did I get a second tax bill after buying in Torrey Highlands?
- The supplemental bill is separate from the regular secured bill. It reflects the difference between your new assessed value and the prior value for the time after your closing date.
How is the supplemental tax calculated for 92129 and 92127 homes?
- The county multiplies the increase in assessed value by your combined tax rate, then prorates it for the days left in the fiscal year. Local levies and Mello-Roos can increase the rate.
Who is responsible for paying the supplemental bill after closing?
- The county bills the owner of record, usually the buyer. Payment responsibility can also be allocated in the purchase agreement and reflected through escrow.
When are supplemental taxes due in San Diego County?
- Supplemental bills have their own mailing and due dates that are separate from the regular bill. Check the Treasurer–Tax Collector for the specific deadlines on your notice.
Can I appeal my supplemental assessed value in San Diego?
- Yes. You can file with the County Assessment Appeals Board. The window is typically 60 days from the mailing date on the supplemental notice or the regular July to September filing period, whichever is later.
Do Mello-Roos in Torrey Highlands affect my supplemental bill?
- Yes. If your parcel has Mello-Roos or other special assessments, your combined tax rate is higher, which increases the supplemental amount.
Will my mortgage escrow account pay the supplemental bill automatically?
- Not always. Some servicers do not process supplemental bills unless you ask. Contact your servicer to confirm their process or to adjust monthly escrow contributions.
