California Property Tax Appeal
How to Appeal Your Property Taxes in Santa Clara County (2026)
Santa Clara County sits at the heart of Silicon Valley, where home values are high enough that even a modest over-assessment translates into a painful tax bill. When the market softens after a run-up, assessments can stay elevated — and here, correcting that is more worthwhile than almost anywhere in the state simply because the dollars per point are so large.
Two Santa Clara specifics shape your strategy. First, the formal deadline is September 15, noticeably earlier than the November 30 many California counties use — miss it and you wait a year. Second, the formal filing fee is steep, which makes the free informal path especially attractive: you can request a Decline-in-Value review from the Assessor by August 1 at no charge, and many reductions are settled there without paying the formal fee at all.
This page lays out the Santa Clara County process in full — the early September 15 deadline, the form, the fee, and the free informal-first route — plus an honest verdict on whether your assessment is actually too high.
Santa Clara County appeal — at a glance
- Appeal deadline
- July 2 – September 15
- Filing fee
- $290
- Appeal form
- BOE-305-AH
- Assessor's office
- (408) 299-5001
Check your Santa Clara County home in minutes
Enter your address and get an honest, comparable-sales analysis of whether you're overassessed — $9.99, with 3 years of monitoring included.
Analyze my assessmentFlat fee. You keep 100% of your tax savings.
Is your Santa Clara County home overassessed?
California property tax bills run roughly 1.1%–1.25% of a home's assessed value. At that rate, an assessment that's $50,000 too high costs a homeowner on the order of $550–$625 every single year — and it compounds until someone corrects it.
The only way to know is to compare your assessed value against what similar nearby homes actually sold for. That's exactly what a Numa analysis does: real comparable sales, an honest overassessed / fairly-assessed verdict, and a conservative savings estimate — for $9.99, with 3 years of monitoring included.
How to appeal in Santa Clara County, step by step
- 1
Confirm your home is overassessed
Your case rests on recent sales of comparable homes. Gather a few similar properties nearby that sold recently, adjust for differences in size, age, and condition, and check whether they came in below your assessed value. This is the most time-consuming part of an appeal, and the quality of those comparables is what decides it.
- 2
Request an informal review with the Assessor
In Santa Clara County, start with an informal Decline-in-Value (Proposition 8) review — often the fastest path, resolved without a hearing. Get the informal review form.
- 3
File a formal appeal if needed
If the informal review doesn't resolve it, file form BOE-305-AH with the Assessment Appeals Board — before the September 15 deadline. You can file online, by mail, or in person.
- 4
Present your evidence
Your comparable-sales evidence is what wins the appeal. Numa's $24.99 packet assembles it into a ready-to-file case — and if the informal review fails, the formal Appeals Board packet is included at no extra charge.
Do it yourself, or let Numa do the hard part
You can absolutely appeal on your own — the deadline, form, and steps above are all you need to file. The catch is Step 1: building the comparable-sales evidence that actually wins. Here's the honest trade-off.
Do it yourself
- Free
- Typically 5–10 hours of work
- You find, adjust, and score the comps yourself
- Amateur evidence is the top reason appeals fail
- No easy way to know if you should file at all
With Numa
- $9.99 analysis, done in minutes
- Real comparable sales, scored the way the county does
- An honest verdict — including “don't file, you're fairly assessed”
- 3 years of monitoring included
- Optional $24.99 ready-to-file evidence packet if you're overassessed
Santa Clara County key dates
- Appeal window: July 2 – September 15
- Residential filing fee increases to $290/parcel effective June 1, 2026. Contact assessor for informal review before filing formal appeal.
- Prop 8 (decline in value): Informal request to assessor by August 1 (free); formal appeal within regular deadline (July 2 – September 15).
Santa Clara County property tax appeal — FAQ
What is the property tax appeal deadline in Santa Clara County?
The regular appeal window runs July 2 through September 15. Residential filing fee increases to $290/parcel effective June 1, 2026. Contact assessor for informal review before filing formal appeal.
How much does it cost to appeal property taxes in Santa Clara County?
The filing fee is $290.
Do I have to go to a hearing to lower my assessment?
Often not. In Santa Clara County you can request an informal review (a Decline-in-Value / Proposition 8 request) with the Assessor first — many reductions are resolved this way without a formal hearing. If the informal review doesn't succeed, you can file a formal appeal with the Assessment Appeals Board.
How do I know if my Santa Clara County home is overassessed?
Your home is overassessed if comparable homes recently sold for less than your assessed value. Numa runs that comparison for you — the same comparable-sales method the county uses — and gives you an honest verdict for $9.99, with 3 years of monitoring included.
What form do I use to appeal in Santa Clara County?
Formal appeals use form BOE-305-AH, filed with the Assessment Appeals Board. Numa's packet fills in the evidence and shows you exactly how to file it.
Check your Santa Clara County home in minutes
Enter your address and get an honest, comparable-sales analysis of whether you're overassessed — $9.99, with 3 years of monitoring included.
Analyze my assessmentFlat fee. You keep 100% of your tax savings.