TaxDrop currently serves Texas only. We're not taking Contra Costa County appeals yet. Join the waitlist and we'll let you know when we launch in California.
β Free county guide - how a Contra Costa County appeal works
β Join the waitlist - no payment and no filing. We'll just tell you when TaxDrop opens here.
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TaxDrop currently serves Texas only. We're not taking Contra Costa County appeals yet. Join the waitlist and we'll let you know when we launch in California.
β Free county guide - how a Contra Costa County appeal works
β Join the waitlist - no payment and no filing. We'll just tell you when TaxDrop opens here.
TaxDrop currently serves Texas only. Join the waitlist and we'll email you when we launch here.
TaxDrop currently serves property owners in Texas only. We aren't filing appeals or selling filing packets in California right now. If you'd like to hear when we launch in Contra Costa County, join the waitlist. Joining doesn't sign you up for a service or file anything for you.
In the meantime, here's general information about how a property tax appeal works in Contra Costa County. Check the county's official site for current deadlines and fees.
If you just opened your Contra Costa County property tax bill and felt that familiar punch to the gut, you're not alone. Homeowners across Walnut Creek, Concord, Richmond, and Martinez are watching their tax bills climb while their home values fluctuate wildly. The worst part? Many are paying hundreds more than they legally owe because the Assessor's Office made valuation errors that go unchallenged year after year.
Here's what most Contra Costa County homeowners don't realize: the Assessment Appeals Board exists specifically to correct these mistakes. Last year alone, they approved reductions for thousands of properties where owners simply presented the right evidence. The problem isn't that appeals don't work β it's that most people don't know how to build a winning case or don't have months to navigate the county's bureaucracy.
Your property's assessed value determines your entire tax bill, but the county assessor's office processes over 400,000 properties with limited staff and outdated methods. They rely heavily on automated systems that can't account for your home's specific condition, neighborhood changes, or recent comparable sales that might lower your value. Properties in areas like Pleasant Hill and Antioch are particularly prone to over-assessment because rapid market changes make accurate valuations nearly impossible.
The appeals process exists because the county knows their initial assessments aren't perfect. They expect property owners to challenge questionable valuations β but only if you know what evidence to present and how to present it properly. Miss a deadline or submit incomplete documentation, and you're stuck paying the inflated amount for another full year.
The deadline to file your Contra Costa County property tax appeal is firm β typically February 15th for most properties. Miss it, and you're locked into paying whatever the assessor determined, regardless of whether it's accurate. This isn't about gaming the system; it's about ensuring you pay exactly what you legally owe, nothing more.
TaxDrop currently operates in Texas. See our Texas property tax guide.
Step 1: Review Your Assessment
Receive Assessed Value Notice by July 1 showing property valuation.
Step 2: File Your Appeal
Submit Assessment Appeal Application with supporting evidence between July 2 β September 15.
Step 3: Application Review
Clerk reviews application and schedules hearing (60-90 days after filing).
Step 4: Hearing Preparation
Gather comparable sales data, appraisals, and documentation.
Step 5: Appeals Board Hearing
Present case to Board panel (typically 4-9 months after filing).
Step 6: Decision & Adjustment
Board issues written decision; if successful, assessed value reduced and tax refund issued (30-60 days after hearing).
Filing Deadlines:
Required Documents:
Where to Submit:
Contra Costa County Assessment Appeals Board, 625 Court St, Martinez, CA 94553
Official resources:
The deadline to file a property tax appeal in Contra Costa County is September 15th or within 60 days of your assessment notice mailing date, whichever is later. Missing this deadline means you'll wait until next year to challenge your assessment. Property owners in Martinez, Concord, and Walnut Creek should mark their calendars to avoid missing potential savings.
Not yet. TaxDrop currently serves Texas only. Join the waitlist on this page and we'll let you know when we launch in California.
You can check your property's assessed value online through the Contra Costa County Assessor's website by entering your address or parcel number. The site shows your current assessed value, taxable value, past assessments, and any exemptions. This is your first step to determine if your Martinez, Concord, or Walnut Creek property is overassessed.
Your Contra Costa County property may be overassessed if similar homes in your Martinez, Concord, or Walnut Creek neighborhood sold for 10% or more below your assessed value. Market downturns, property damage, or outdated comparable sales data often lead to overassessments. Comparing your assessed value to recent sales of similar properties is the best indicator.
Yes, landlords and investors can appeal property taxes on rental and commercial properties throughout Contra Costa County, including Martinez and surrounding cities. Investment property appeals often yield larger dollar savings due to higher property values. Successful appeals improve cash flow and property returns for California real estate investors.
Missing the Contra Costa County property tax appeal deadline means you cannot appeal your current assessment and must wait until next year's appeal period. You'll continue paying taxes based on the potentially inflated assessment for another full year. However, you can prepare early by reviewing your assessment and gathering evidence for next year's appeal.