Your First San Francisco Property Tax Bill: Supplemental Taxes, the 1.18% Rate, and the Dec. 10 Deadline

FY 2026–27 rate

1.18162182%

Before parcel taxes and other direct charges

First installment

Dec. 10

Delinquent after 5 p.m.; 10% penalty

$2M annual estimate

$23,632

Purchase price × current rate

Data: FY 2026–27 tax rate; owner-supplied closed-sale medians through October 31, 2026.

The first San Francisco property-tax surprise is usually not the rate. It is the second envelope.

I have been hit with supplemental tax bills in the tens of thousands, and so have clients. The mistake is assuming the property taxes handled at closing, or collected by the lender each month, settle the first year. They often do not.

My advice is simple: after closing, keep a separate tax reserve until you have seen both the regular bill and every supplemental bill. Then confirm who is paying each one. Do not assume escrow will sort it out.

Why a new owner can receive two tax bills

San Francisco sends the regular secured property-tax bill based on the value already on the tax roll. A purchase triggers a new assessment. When the Assessor replaces the prior value with the new value, the Treasurer issues a supplemental bill for the difference.

That supplemental bill is in addition to the annual bill. It is not a duplicate. It catches the property up from the first day of the month after the sale through the end of the fiscal year. A purchase from January through May can produce two supplemental bills because the adjustment crosses into another fiscal year.

This is why the prior owner’s low Proposition 13 assessment matters to your first-year cash flow. The larger the gap between that value and your new assessment, the larger the supplemental assessment can be.

What the 1.18162182% rate means

For fiscal year 2026–27, San Francisco’s secured property-tax rate is 1.18162182%. As a quick annual estimate, multiply the expected assessed value by 0.0118162182.

On a $2 million home, that is about $23,632 a year before the additional lines on the bill. It is a useful carrying-cost estimate. It is not the formula for the supplemental bill itself.

Estimate the supplemental bill, not just the annual tax

The rough formula is: new assessed value minus prior assessed value, multiplied by the tax rate, multiplied by the remaining-fiscal-year factor.

Suppose a $2 million purchase replaces a $1 million prior assessment. The annualized tax on that $1 million difference is about $11,816. If the sale occurred in October, the adjustment starts November 1 and the state factor is 8/12, producing a rough supplemental estimate of $7,877. The actual bill can differ, so use the City’s supplemental tax calculator and then pay the amount on the bill.

The important number is not simply your purchase price. It is the gap between your new assessment and the old one, plus the closing month.

What recent San Francisco prices imply

The median San Francisco house closed at $2.105 million in 2026 through October 31 across 1,640 sales. At the current rate, that points to about $24,873 in annual base tax. The 2025 median was $1,700,802, or about $20,097 at the same rate. The median 2026 condo closed at $1,266,500, implying about $14,965.

Those are not supplemental-bill forecasts. They show the annual scale a buyer should be ready to carry after reassessment. A separate September market report put the single-family median at $2.054 million, which is directionally consistent with the owner-supplied year-to-date figure.

If that larger carrying cost changes the ceiling, revisit what different San Francisco budgets bought in 2026 before stretching the offer. Taxes belong in the ceiling alongside the cash plan for an appraisal gap, not in a later folder marked closing details.

Escrow does not mean every bill gets paid

An impound account usually collects money for the regular annual property-tax bill. Supplemental bills are commonly sent directly to the owner and may not be paid from that account. The only safe answer is the one your loan servicer gives you for the specific bill number.

This is also worth confirming before you waive protections. Our guide to San Francisco offer contingencies explains the larger contract decision; the tax reserve is part of knowing how much cash remains after closing.

1. Open every tax notice even if your monthly payment includes taxes.
2. Check whether the document is a regular secured bill, supplemental bill, or assessment notice.
3. Ask the servicer in writing whether it will pay that exact bill.
4. If not, pay the Treasurer directly by the bill’s deadline and keep the confirmation.
5. After reassessment, review the escrow analysis. A higher annual bill can raise the monthly payment or create a shortage.

The dates that matter

A 10% penalty on a $15,000 installment is $1,500. That is too much money to lose because a bill was sitting unopened or because the borrower and servicer each assumed the other would pay it.

Can you appeal the new value?

Yes. A supplemental assessment appeal generally must be filed within 60 days of the notice date or postmark, whichever is later. Paying the tax and appealing the value are separate matters, so an appeal does not justify missing the payment deadline.

For a normal arm’s-length purchase, I would keep expectations modest. California generally treats the recent purchase price as the property’s fair market value unless there is persuasive evidence otherwise. An appeal makes more sense when the assessment does not match the transaction or the property facts, not simply because the resulting bill is painful.

Why your total will not match the simple rate

The 1.18162182% calculation is the base. San Francisco bills can also include parcel taxes, direct charges and special assessments. The homeowners’ exemption reduces assessed value by $7,000 for a qualifying principal residence, which saves roughly $83 at the current rate. It does not reduce the bill by $7,000.

Read the direct-charge lines rather than forcing the total to match a calculator. A condo owner should also remember that HOA dues and assessments are separate from the City’s property-tax bill.

What I would do after closing

• Set aside the annual tax estimate plus a separate supplemental reserve.
• Save the closing statement and note the prior assessed value if available.
• Use the Assessor’s calculator once the transfer appears in the records.
• Watch the mail for the assessment notice and the Treasurer’s bill.
• Verify payment responsibility with the servicer bill by bill.
• Calendar December 10 and April 10, then pay early enough to document receipt.

The second bill should not feel like a second purchase. Budget for the assessment gap before you close, keep the reserve until the paperwork catches up, and treat every envelope from the Assessor or Treasurer as your responsibility until someone confirms otherwise in writing.