Peninsula Real Estate Guide
Property Taxes Compared: South San Francisco vs. Belmont vs. San Carlos
Why the base rate is nearly identical, and where the real differences actually hide
|
1.17% South San Francisco Median Effective Rate |
~1.2% to 1.25% County Average, Belmont & San Carlos |
$9,758 Median County Tax Bill |
Mello-Roos Where the Real Variance Lives |
All three of these cities sit in San Mateo County, which means they share the same fundamental property tax framework. But the effective rate you actually pay can still differ meaningfully depending on your specific address, and understanding why matters before you compare a purchase across these cities.
The Base Rate Is Nearly Identical Everywhere
Under Proposition 13, every property in California is taxed at roughly 1% of its assessed value, plus an additional amount to cover voter-approved local bonds and special assessments. San Mateo County’s overall average effective rate runs around 1.23% to 1.25%, and Belmont and San Carlos both track close to that county average, since neither carries unusually large voter-approved bond obligations relative to their neighbors.
Why South San Francisco Runs Slightly Lower
A Genuinely Different Local Levy Mix
South San Francisco’s median effective property tax rate runs around 1.17%, slightly below the county average. That rate reflects the county base levy combined with local school district levies and Mello-Roos Community Facilities Districts that vary meaningfully by specific subdivision within the city. Newer developments, particularly around the biotech and Gateway corridor, are more likely to carry these special district assessments than the city’s older, established residential neighborhoods.
A Side-by-Side Comparison
| City | Typical Effective Rate | Key Local Factor |
| South San Francisco | ~1.17% | Mello-Roos varies by subdivision, especially newer development |
| Belmont | ~1.2% to 1.25% | Tracks close to county average, few special districts |
| San Carlos | ~1.2% to 1.25% | No additional city transfer tax; rate tracks county average |
What Actually Drives Your Real Bill
Given how similar the rates are across all three cities, your purchase price, not your city, is by far the biggest factor in your actual annual bill. A $1.1M South San Francisco home and a $2.65M San Carlos home will differ enormously in total tax dollars even though their rates land within a fraction of a percentage point of each other.
What to Actually Check Before Buying
| Ask specifically whether a South San Francisco property carries a Mello-Roos assessment, particularly in newer developments |
| Use the San Mateo County Assessor’s property tax look-up tool for the exact current bill on any specific address |
| Remember that your own tax bill resets to your purchase price under Prop 13, regardless of what the seller was paying |
| Factor property tax into your monthly budget alongside price, since it compounds with a large loan amount either way |
Key Takeaway
Property tax rates across South San Francisco, Belmont, and San Carlos are close enough that they shouldn’t drive your city choice on their own. The real variable worth checking is whether a specific South San Francisco property carries a Mello-Roos assessment.
Frequently Asked Questions
Which of these three cities has the lowest property tax rate?
South San Francisco, at a median effective rate of around 1.17%, slightly below the county average.
What is a Mello-Roos assessment?
A special local district assessment, common in some newer developments, that adds to your base property tax bill.
Does San Carlos have any special tax districts?
Generally fewer than South San Francisco’s newer developments; its rate tracks close to the county average.
Does moving between these cities reset my property tax base?
Yes, unless you qualify for a Prop 19 base year transfer, your tax resets to your new purchase price regardless of which city you move to.
| Related Reading | |
| San Carlos Property Tax Rates: A Buyer’s Guide | A deeper look at San Carlos specifically. |
| Prop 19 and Inheriting Property on the Peninsula | Understand base year transfers across any of these cities. |
| South San Francisco, Belmont, and San Carlos: A 2026 Market Snapshot | Compare pricing alongside these tax figures. |
| The Real Closing Costs to Sell a House in San Carlos | See how transfer tax compares alongside ongoing property tax. |
Want the Exact Tax Bill for a Specific Property?
I can help you look up the real current tax figure for any home you’re considering.
Holly Noto | Coldwell Banker Realty | DRE#01244498, DRE#01908304
580 El Camino Real, San Carlos, CA 94070
650.544.6185 | [email protected]
Tax rate figures reflect Ownwell and San Mateo County Assessor data as of 2026 and can vary by specific parcel and assessment district. This content is not tax advice; consult the County Assessor or a tax professional for figures specific to a property.
