The supplemental property tax bill after you buy in San Diego
Quick answer: When you buy, the County reassesses the home to your price. The supplemental bill is your price minus the seller's assessed value, times the tax rate, times the share of the July to June fiscal year that is left. It is mailed to you, not your lender, even if you have an impound account. Close between January 1 and May 31 and you get two bills.
This is the bill nobody mentions at the closing table. It shows up a few months after you move in, and it is not a mistake. California law (Revenue and Taxation Code sections 75 to 75.72) puts your new assessed value into effect right away instead of waiting for the next annual bill.
The math on a real example
- You buy for $900,000. The seller's assessed value was $400,000.
- Net supplemental value: $500,000.
- At the 1% base rate: $5,000 a year. Your actual rate adds voter-approved bonds, so the real number runs a bit higher.
- You close in October. The new value takes effect November 1, which leaves 8 of 12 months (factor .67).
- Supplemental bill: about $3,350, before bonds.
The proration factors and method come from the California State Board of Equalization. The County mails the bill. Due dates vary by bill.
One bill or two
| You close in | Supplemental bills |
|---|---|
| June through December | One bill, for the rest of the current fiscal year |
| January through May | Two bills: the rest of the current fiscal year, plus the full next fiscal year starting July 1 |
New construction works the same way. A newly built home or an addition triggers a supplemental bill when it is completed.
Why your impound account does not catch it
Lenders get the annual tax bill. They do not get the supplemental bill. It goes straight to the owner by law. If it goes unpaid because you thought the lender had it, the County cannot waive the penalty for that reason. When it arrives, pay it or call your servicer right away to decide who pays.
How it fits your mortgage
On a purchase we estimate property tax from your price, not the seller's current bill. So the PITI and DTI number on your pre-approval already reflects the reassessment. What it does not cover is this catch-up bill. Keep cash for it after closing, separate from the impound deposit you fund at escrow. See cash to close breakdown and purchase closing costs. Mello-Roos is its own line: Mello-Roos and your payment.
Living in the home? File for the homeowners' exemption. It can apply to a supplemental bill too if you occupy within 90 days of purchase and the home was not already getting it. Questions about the value go to the Assessor. Appeals of a supplemental assessment must be filed within 60 days of the mailing date on the bill.
Get a payment built on your price at get pre-approved San Diego. Company NMLS 2394495. Amir Nurani NMLS 197458. Call (619) 366-9494.
Sources: California State Board of Equalization, Supplemental Assessment. San Diego County Treasurer-Tax Collector, Supplemental Tax FAQs. California Revenue and Taxation Code sections 75 to 75.72.
Frequently asked questions
Not automatically. Supplemental bills are mailed to the owner, not the lender. Pay it or call your servicer right away. A mix-up with the lender does not excuse a late penalty.
If you closed between January 1 and May 31, the first bill covers the rest of the current fiscal year and the second covers the full next fiscal year starting July 1.
Yes. The supplemental bill comes in addition to the annual bill. Both have to be paid.
Yes. If you paid less than the prior assessed value, the reassessment can be negative and the County issues a refund.
Not on our files. We estimate tax from your purchase price so PITI and DTI reflect the reassessment. Call (619) 366-9494.
Want a payment built on your price, not the seller's tax bill?
Send the price and down payment. We build PITI from your purchase price and flag the cash to keep for the supplemental bill.
Get Pre-Approved(619) 366-9494 · Amir Nurani · NMLS #197458
Left Coast Leaders, Inc. · NMLS #2394495 · DRE #02191517 · Equal Housing Lender · San Diego County and Riverside County · San Diego, CA