Buying a home in Millbrae is exciting, but the property tax bill can be confusing if you are new to California’s system. If you want a clear picture of your monthly payment and any one-time surprises, understanding how taxes work here will help you plan with confidence.
In this guide, you will learn how Millbrae property taxes are calculated, what supplemental bills are, when payments are due, and how to budget so nothing catches you off guard. Let’s dive in.
How Millbrae property taxes work
California’s property tax system is built on Proposition 13. Here are the essentials you should know as a Millbrae buyer:
- The base ad valorem tax is 1% of your assessed value.
- Your assessed value usually resets to your purchase price when you buy. After that, it can increase by up to 2% per year unless there is new construction or another reassessment trigger.
- On top of the 1% base, voters can approve additional charges. These may include school and local agency bonds, parcel taxes, and special district assessments. Some neighborhoods may also have Mello-Roos community facilities district taxes.
When you buy in Millbrae, the San Mateo County Assessor sets the assessed value and the Treasurer-Tax Collector issues the bill and collects payment. Your specific parcel will show the exact components that apply.
What you might pay
Your annual tax is the sum of percentage-based charges and any fixed-dollar assessments that apply to the parcel.
- Conceptual formula: Annual tax is approximately your assessed value multiplied by the combined rate (1% base plus local rates), then add any fixed parcel taxes and special assessments.
- Typical total rate range: Many Bay Area homes fall around 1.1% to 1.4% of assessed value, plus any fixed charges. The actual rate for a given home varies by parcel. Always verify on the property’s tax bill or with county records.
Hypothetical examples
Example A, simple percentage: You buy at $1,600,000 and the total rate is 1.20% (1% base plus 0.20% local). Annual tax is $1,600,000 × 1.20% = $19,200, or $1,600 per month if escrowed.
Example B, adds a fixed parcel tax: Same $1,600,000 assessed value with a 1.10% rate plus a $400 parcel tax. Annual percentage portion is $17,600, plus $400 equals $18,000 total, or $1,500 per month if escrowed.
These are illustrations only. Your parcel’s bill will show the precise voter-approved items and assessments that apply.
Supplemental tax bills after you buy
A supplemental tax bill is a separate county bill that captures the difference when your assessed value changes during the fiscal year. This usually happens when your purchase price is higher than the seller’s prior assessed value.
- How it is calculated: The county figures the difference between your new assessed value and the prior assessed value, applies the total rate, then prorates that amount for the remaining part of the fiscal year.
- Timing: Supplemental bills arrive separately from your regular secured bill. They can show up weeks or even months after closing.
- Who pays: Buyers are typically responsible for supplemental bills unless your purchase agreement specifies otherwise. Some lenders collect an estimate at closing, but many do not, so plan for it as a potential out-of-pocket expense.
- Appeals: If you believe the reassessed value is incorrect, you can file an appeal with the county’s Assessment Appeals Board. An appeal does not usually pause the due date on a supplemental bill.
Hypothetical supplemental example
- Purchase date: March 1
- New assessed value: $1,600,000
- Prior assessed value: $800,000
- Total rate: 1.20%
Annual difference tax is ($1,600,000 − $800,000) × 1.20% = $9,600. Prorated for March through June, that is 4 months of the fiscal year: $9,600 × (4/12) = $3,200 as a separate supplemental bill. If your lender did not collect for this, you would pay that amount directly when billed.
Due dates, penalties, and escrow accounts
California’s property tax fiscal year runs from July 1 to June 30.
- First installment is due November 1, delinquent after December 10.
- Second installment is due February 1, delinquent after April 10.
- Late payments typically incur a 10% penalty for delinquent installments, plus additional fees. Long-term delinquency can trigger further penalties and legal actions. Exact amounts are set by the county.
Most lenders use an escrow or impound account for taxes and insurance. You pay 1/12 of the annual tax each month, the lender builds the balance, then pays the county when due. Lenders also require an initial deposit and a small cushion. Policies vary on whether lenders estimate and collect supplemental taxes at closing, so confirm their approach and budget accordingly.
Budget with confidence in Millbrae
Use these steps to estimate and plan your monthly housing costs:
- Determine your likely assessed value. It is usually your purchase price when you buy.
- Review the current year property tax bill or county parcel detail for the home you are considering. Identify the total percentage rate and any fixed-dollar charges like parcel taxes or special assessments.
- Estimate your annual tax using the formula: assessed value multiplied by the combined rate, plus any fixed assessments. Divide by 12 for a monthly estimate.
- Ask your lender whether they plan to estimate and collect a supplemental tax amount at closing. If not, set aside funds in case a supplemental bill arrives.
- Build a budget buffer. Many buyers keep one to two months of mortgage payments, or the estimated supplemental amount, in reserve during the first year.
Buyer checklist: what to request and verify
- Current year property tax bill for the property.
- Preliminary title report or escrow instructions that list assessed value and any special assessments.
- Information on parcel taxes, school bonds, special district assessments, and any Mello-Roos for the property.
- Lender questions to ask:
- Will you open an escrow or impound account for taxes and insurance?
- Will you estimate and collect any supplemental tax at closing?
- How large a cushion will you require in the escrow account?
- County offices to contact if anything is unclear:
- San Mateo County Assessor’s Office for assessed value questions and appeals.
- San Mateo County Treasurer-Tax Collector for billing, due dates, penalties, and payment options.
Local insights for Millbrae buyers
- Expect parcel-by-parcel variation. The biggest differences between nearby homes often come from voter-approved bonds, parcel taxes, and any Mello-Roos district charges.
- Review the actual tax bill lines. This is the best way to confirm your combined percentage rate and any fixed charges for the specific address.
- Plan for the first year. If the seller’s assessed value is much lower than your purchase price, your supplemental bill could be significant. Build that into your cash plan from day one.
Final thoughts and next steps
A clear tax plan can make your Millbrae purchase smoother and your first year of ownership more predictable. Focus on three things: confirm your likely assessed value, verify parcel-specific charges, and plan ahead for a possible supplemental bill. With those pieces in place, you will have a solid monthly budget and fewer surprises after closing.
If you want help reviewing a specific Millbrae property tax bill or building a realistic monthly housing budget, connect with Vilma Palaad. You will get local guidance, practical numbers, and a plan that fits your goals.
FAQs
Will I owe a supplemental property tax after buying in Millbrae?
- Usually yes if your new assessed value is higher than the seller’s prior assessed value, since the county prorates the difference for the rest of the fiscal year and bills it separately.
How do I estimate my monthly property tax in Millbrae?
- Multiply your expected assessed value by the combined rate (1% base plus local rates), add any fixed parcel taxes or assessments, then divide by 12 for a monthly estimate.
Will my lender pay my supplemental tax bill?
- It depends; some lenders collect an estimate at closing, but many do not, so confirm with your lender and consider setting aside cash for a possible supplemental bill.
How can I tell if a Millbrae home has Mello-Roos or parcel taxes?
- Check the property’s tax bill and preliminary title report, review municipal disclosures, and ask your agent; Mello-Roos and parcel taxes appear as separate line items on the bill.
What if I believe my Millbrae assessed value is too high?
- You can file an assessment appeal with the county’s Assessment Appeals Board following county procedures and deadlines; note that appeals typically do not pause tax due dates.
When are San Mateo County property taxes due each year?
- The first installment is due November 1 and delinquent after December 10, and the second is due February 1 and delinquent after April 10, with penalties and fees for late payment.
