San Diego property tax, explained

What is the property tax rate in San Diego County?

San Diego County property tax is not one rate. The County Treasurer-Tax Collector writes the formula as 1% of value, plus voter-approved bonds, plus fixed charge special assessments including Mello-Roos — and only the first of those three is the same for every parcel.

Each term does something different. The 1% is the Proposition 13 base, charged on the full cash value the Assessor holds for the property. Voter-approved bonds are the debt a particular jurisdiction’s own voters approved — school and water district bonds are the usual ones — so they vary by where the parcel sits and what its voters have passed.

Fixed charge special assessments are the term that is not about value at all. The county describes them as levies on real property to pay for improvements or services, from mosquito surveillance to vector disease control, and Mello-Roos is one type of them. That is why two houses worth the same amount, a mile apart, can carry annual bills that differ by thousands.

Which districts reach a given community, and what they charge this fiscal year, is what the Mello-Roos pages exist to answer — traced to the County Auditor’s active district list rather than estimated.

Why is my San Diego property tax higher than my neighbor's?

A San Diego property is reassessed when it changes hands, and between sales Proposition 13 caps the increase in assessed value at 2% a year, indexed to the California Consumer Price Index. So a neighbor who bought decades ago is taxed on a decades-old basis, and you are taxed on what you paid.

That single rule explains most of the difference between two bills on the same street, and it is why a seller’s current tax figure is close to useless for budgeting a purchase. The number to model is the one that follows reassessment at your purchase price, not the one on the bill you were shown.

It also means the gap widens the longer the neighbor holds. In the long-held coastal communities this is the dominant property tax conversation — more so than special taxes, which most of that housing predates entirely.

What is a supplemental tax bill, and why did I get one?

A supplemental tax bill is the catch-up charge for the difference between what a San Diego property was assessed at before you bought it and what it is assessed at after. It arrives separately from the annual bill, generally six to twelve months after the sale closes.

The county sets it out plainly: anytime a property is sold to a new owner or new construction is completed, state law says it must be reassessed. The annual secured bill was already calculated on the prior owner’s value as of January 1, so the supplemental covers the gap, prorated for the months left in the fiscal year.

The county’s own worked example: a property bought on September 15 at a new market value of $450,000 with a prior assessed value of $350,000 leaves a supplemental taxable value of $100,000. Nine months remain in the fiscal year, so that is prorated to $75,000, and at the approximate 1% rate the supplemental bill is about $750.

Two things catch buyers. It is not collected through an impound account — a lender paying the annual bill will generally not pay this one — and it can arrive long enough after closing that the money has been spent on the house. It is a budget item, not a surprise, provided somebody tells you in advance.

When are San Diego property taxes due?

San Diego County annual secured tax bills are mailed beginning in October. The first installment is due November 1 and becomes delinquent after December 10; the second is due February 1 and becomes delinquent after April 10.

Where a delinquency date falls on a weekend or a holiday, payment is accepted until the close of the next business day. Failure to receive a bill does not excuse the delinquency or the penalty, which is the part worth knowing after a move — the Tax Collector mails to the address on the official roll, and updating it is the owner’s job.

Owners with an impound or escrow account generally have the annual installments paid by the lender by those two dates and receive an information copy of the bill rather than a demand. That arrangement does not usually extend to the supplemental bill.