California Sales Tax vs California Use Tax – A Business Owner’s Guide to CDTFA Audits
California’s tax system can be confusing, especially for business owners navigating sales tax, use tax, and excise tax obligations. The California Department of Tax and Fee Administration (CDTFA) enforces these rules, and when discrepancies arise, they audit.
For many businesses, a CDTFA audit starts with something as simple as an exemption error, a missing resale certificate, or a purchase from an out-of-state vendor. But those small issues can quickly escalate into significant liabilities.
At Milikowsky Tax Law, we represent business owners through CDTFA audits to minimize exposure, correct errors, and keep operations running.
The Role of the CDTFA
The CDTFA is responsible for administering California’s sales and use taxes, as well as various excise taxes on fuel, tobacco, cannabis, and other goods.
Their goal: to ensure businesses collect and remit the correct amount of tax.
But enforcement is not just about compliance, it’s about revenue. CDTFA audits generate substantial collections each year, which means audit activity is both frequent and aggressive.
Sales Tax vs. Use Tax vs. Excise Tax: What’s the Difference?
Sales Tax
- Who pays it: The end customer.
- Who collects it: The seller, who must then remit it to the state.
- When it applies: On most tangible goods sold in California, unless a valid exemption applies (e.g., resale or manufacturing).
Use Tax
- Who pays it: The purchaser.
- When it applies: When taxable goods are purchased without paying California sales tax, for example, buying equipment online from an out-of-state seller who doesn’t collect CA tax.
- Why it matters: The CDTFA uses cross-referenced purchase data (from Amazon, FedEx, and others) to identify unpaid use tax and trigger audits.
Excise Tax
- Who pays it: Varies, often included in the price of regulated goods (like fuel, alcohol, or cannabis).
- When it applies: On specific industries or products subject to additional regulation.
- Why it matters: Excise tax audits often overlap with sales/use tax audits in industries like fuel distribution and cannabis.
Industries Most at Risk for CDTFA Audits
The CDTFA targets sectors where cash transactions, inventory movement, or exemption claims create audit complexity.
High-risk industries include:
- Construction and contracting (especially subcontractors using materials in multiple jurisdictions)
- Auto sales and repair shops
- Restaurants and hospitality (tip reporting, POS underreporting)
- Manufacturing and fabrication (misapplied resale certificates or exemption misuse)
- E-commerce and online retailers (out-of-state sales and use tax nexus issues)
- Cannabis, tobacco, and alcohol (dual exposure to excise and sales tax audits)
- Medical device suppliers and distributors (mixed taxable and exempt sales)
Case Story: When a Sales Tax Audit Turns Costly
A San Diego-based marine equipment dealer came to our firm after receiving a CDTFA audit notice. The issue started when an auditor flagged several large out-of-state purchases of boat engines. Because the dealer hadn’t paid use tax on those purchases, assuming his resale certificate covered them, the CDTFA assessed tax, penalties, and interest.
Our team reviewed purchase records, vendor invoices, and shipping documentation.
We proved that several “taxable” transactions were actually resales to registered dealers, not end consumers. By properly documenting the exemptions and negotiating with the auditor, we reduced a $140,000 proposed liability to under $30,000, saving the business owner over $100,000.
The takeaway: Paperwork matters. Missing documentation is the #1 cause of inflated audit assessments.
What Triggers a CDTFA Audit
- Large changes in reported sales or deductions
- Unfiled or late tax returns
- Sales reported inconsistently with industry averages
- High exempt sales without supporting resale certificates
- Use tax not reported on out-of-state purchases
- Complaints or whistleblower tips
The CDTFA may audit three years of returns, but if fraud or willful evasion is suspected, they can go back eight years or more.
How to Prepare for a CDTFA Audit
- Gather all sales and purchase records.
Include invoices, resale certificates, and bank statements. - Reconcile your returns.
Ensure sales tax filings align with your income tax and accounting records. - Identify exposure early.
A voluntary disclosure or pre-audit review can minimize penalties. - Involve legal counsel immediately.
Auditors work for the state, their goal is to collect revenue, not educate.
FAQs: California Sales Tax Audits
Q: What’s the difference between a CDTFA audit and an IRS audit?
A: The CDTFA audits sales and use taxes, not income taxes. But their findings can trigger state or federal inquiries if inconsistencies are found.
Q: How long does a CDTFA audit take?
A: Most audits take 6–12 months, depending on complexity, document availability, and whether you dispute findings.
Q: Can the CDTFA audit closed businesses?
A: Yes. The CDTFA can audit closed or sold businesses if the liability period remains open. Sellers are often surprised when a buyer’s request for a tax clearance certificate triggers an audit.
Q: What happens if I can’t find all my records?
A: The CDTFA will estimate your liability, often using inflated industry ratios. Legal representation can help challenge these estimates.
Q: Can a CDTFA audit lead to criminal charges?
A: Yes, in cases involving fraud or intentional evasion. That’s why early legal involvement matters.
Protect Your Business Before the CDTFA Calls
A CDTFA audit can disrupt your operations, drain resources, and expose years of financial data. At Milikowsky Tax Law, we understand how the CDTFA operates because we’ve handled hundreds of these cases.
From pre-audit preparation to closing agreements, our goal is simple: we keep your business in business.
