California Form CDTFA-770 is the family of Diesel Fuel Tax refund claim forms issued by the California Department of Tax and Fee Administration (CDTFA) that lets diesel users, ultimate vendors, exempt bus operators, government agencies, and interstate truckers recover state diesel fuel tax paid on fuel used in a nontaxable way. The 770 series includes CDTFA-770-DU (Diesel User), CDTFA-770-DV (Diesel Vendor / Ultimate Vendor), CDTFA-770-DVW (Worksheet), CDTFA-770-DZ (Sales to Ultimate Purchaser), and CDTFA-770-ES (Exempt Sales), plus several supporting schedules.
Diesel tax in California is one of the highest in the country, and CDTFA processes thousands of refund claims each year under the Diesel Fuel Tax Law. According to CDTFA’s most recent published refund data, the agency pays out more than $100 million each year in diesel fuel tax refunds, yet roughly one in four claims is delayed or partially denied because of missing invoices, math errors, or wrong gallon totals. Getting Form CDTFA-770 right is the difference between a fast refund check and months of back-and-forth correspondence.
In this guide, you will learn:
- 📄 What each form in the CDTFA-770 series does and who must file it
- 🧾 The exact documents, gallon records, and invoices to gather before you start
- ✍️ A line-by-line walkthrough of every field on the most-used 770 forms
- 👥 Three full filled-out examples for a farmer, an interstate trucker, and an ultimate vendor
- ⚖️ The deadlines, statutes, and common mistakes that get refund claims denied
What the Form Is and Who Must File It
Form CDTFA-770 is not a single form — it is a series of refund claim forms tied to California’s diesel fuel excise tax program. The state imposes a per-gallon tax on diesel fuel at the rack, and that tax is built into the pump price. When diesel is later used for an exempt purpose — farming, off-highway construction, interstate truck travel, exempt bus service, or sale to the U.S. government — the buyer can claim the tax back using a 770-series form.
CDTFA-770-DU (the Diesel User claim) is filed by end users who buy tax-paid diesel and burn it for a nontaxable purpose. CDTFA-770-DV is filed by ultimate vendors that sell tax-paid diesel to exempt buyers (such as the U.S. government, qualified farmers, or exempt bus operators) and absorb the tax. CDTFA-770-DZ supports DV claims with line-item sales detail. CDTFA-770-ES documents exempt sales by suppliers. CDTFA-770-DVW is the worksheet that ties invoices to gallons. Each form has its own legal hook in the Revenue and Taxation Code (RTC) §§ 60501–60522.
If you are an interstate trucker registered under the International Fuel Tax Agreement (IFTA), you typically reconcile diesel tax on your IFTA return rather than on Form 770-DU, but off-highway gallons consumed inside California still qualify for a 770-DU refund. Farmers using diesel in tractors or irrigation pumps file 770-DU. Bus operators carrying the public under exempt routes file under separate exempt bus operator provisions but use the 770 series for their refund mechanics.
Common misconception: many filers think a 770-DU refund “comes from the IRS” — it does not. The federal off-highway refund is a separate claim filed on IRS Form 4136. The CDTFA-770 series only refunds the California state diesel tax, currently anchored in RTC § 60050.
Before You Start: Documents and Information You Need
Pull every record together before you open the form. CDTFA expects a refund claim to match purchase invoices to the gallon, and a single missing document can pause your file in the refund examination unit for months. The agency’s Publication 117, Filing a Claim for Refund, spells out the proof standard.
Gather these items, at minimum:
- Your CDTFA account number or diesel fuel tax license number, because every claim is keyed to your account; without it, the form is returned unfiled.
- Federal Employer Identification Number (FEIN) or Social Security Number, because CDTFA cross-checks your identity against Franchise Tax Board records.
- All original purchase invoices showing California diesel tax paid, dated within the refund period, because handwritten gas-station receipts without a tax line cannot anchor a refund.
- A gallons-used log by vehicle, equipment, or activity, because CDTFA matches taxable miles to off-highway gallons.
- Equipment list with VINs, serial numbers, and horsepower, because off-road equipment must be identified to qualify for the off-highway exemption.
- A schedule of exempt customers (for DV filers), because the ultimate vendor refund only applies to sales to specific exempt buyers.
- Your prior refund claim number, if any, because CDTFA tracks claim sequencing and rejects duplicate periods.
- Bank account information for direct deposit through CDTFA’s online services, because paper warrants take 4–6 weeks longer to arrive.
If you sell to the U.S. government, also collect a copy of the federal exemption certificate signed by the contracting officer. Missing this single document is the most common cause of a denied DV claim under RTC § 60501.
Where to Get the Form and How to Access It
You can download the current revision of every 770-series form from the CDTFA Forms and Publications library. The forms are fillable PDFs. Always check the revision date in the lower-left corner of page 1 before you start, because CDTFA rejects superseded versions.
The fastest way to file is through the CDTFA Online Services portal, which lets you submit the form, upload supporting schedules, and request direct deposit in one session. If you do not have an online account, you can create one with your CDTFA account number, FEIN, and a recent return amount as the security check. The portal accepts PDF, JPG, and Excel attachments up to 25 MB per file.
If you prefer paper, you can request a mailed copy by calling CDTFA’s Customer Service Center at 1-800-400-7115 or by visiting any CDTFA field office. Paper forms must be printed single-sided in black ink. CDTFA does not accept faxed refund claims because original signatures are required under RTC § 60522.
A common misconception is that the form found through a generic web search is current. Third-party tax sites often host outdated revisions. Always pull the form from the agency page itself, and confirm the revision date matches what CDTFA’s instructions reference. Filing on an outdated revision triggers a “Form Version Invalid” rejection letter, and the clock keeps running on your 3-year statute of limitations.
Step-by-Step: How to Fill Out CDTFA-770 Line by Line
The 770-DU is the workhorse of the series, so the walkthrough below follows that form field by field. The same patterns apply to 770-DV, 770-DZ, and 770-ES, with notes where they differ. Use the exact field labels and box numbers from the official form. Sample entries are italicized so you can tell them apart from instructions.
Box 1 — Claimant Name
This field asks for the legal name of the person or business filing the claim. Enter the name exactly as it appears on your CDTFA registration and your federal tax return. For a sole proprietor, write the individual’s full legal name; for an LLC or corporation, write the entity name as registered with the California Secretary of State.
A specific example: Maria Lopez, who runs a Fresno almond farm as a sole proprietor, writes Maria Lopez in Box 1, not Lopez Farms or Maria’s Almonds. If she filed under a DBA, she would add the DBA on the next line.
A common edge case is a recent name change after marriage or entity conversion. If your CDTFA account still shows the old name, file CDTFA-345, Notice of Business Change before submitting the refund claim, or the refund warrant will be made out to the wrong payee.
A common mistake is entering a “doing business as” name in Box 1 and leaving the legal name off. The consequence is direct: the refund check is issued to a name that does not match your bank account, and your bank rejects the deposit. The most common misconception is that CDTFA “knows who you are” from your account number — it does not assume; it matches the printed name on the form against its master file.
Box 2 — CDTFA Account Number
This field asks for your CDTFA-issued diesel fuel tax account number, sometimes called the permit number. Enter the full account number, including any prefix letters, without dashes or spaces. The number is printed on your registration letter and inside your online services profile.
For example, Carlos Mendez, a long-haul trucker based in Stockton, writes SR FHB 12-345678 exactly as it appears on his diesel user license.
The edge case here is filers who hold multiple CDTFA permits (for example, a sales and use tax permit and a diesel fuel tax permit). Use the diesel fuel tax account number — not the sales tax permit — or the claim will route to the wrong examiner.
A common mistake is mixing up the FEIN with the CDTFA number. The consequence is that the claim is rejected as “Account Not Found,” and you must refile from scratch. The misconception is that CDTFA can look you up by name. With over a million registered accounts in the state, name-only lookups are not done; the account number is the master key.
Box 3 — FEIN or SSN
This field asks for your Federal Employer Identification Number, or your Social Security Number if you are a sole proprietor without an FEIN. Format the FEIN as XX-XXXXXXX and the SSN as XXX-XX-XXXX. CDTFA uses this number to coordinate with the IRS and the Franchise Tax Board.
For example, Maria Lopez enters 123-45-6789 as her SSN because her farm is unincorporated and has no employees.
A common edge case is single-member LLCs. If you are a disregarded entity, use your SSN, not the LLC’s FEIN, unless you have payroll employees and a real FEIN on file.
A common mistake on this field is transposing two digits, which immediately fails the IRS match and triggers a manual review. The misconception is that this field is optional for small refunds. It is not — it is required by RTC § 60521 for every claim regardless of dollar amount.
Box 4 — Mailing Address
This field asks for the address where CDTFA should mail correspondence and, if you do not choose direct deposit, your refund warrant. Use the street address or P.O. Box on file with CDTFA. Write it in standard USPS format with the city, two-letter state code, and ZIP+4.
For example, Carlos Mendez enters 4501 Charter Way, Stockton, CA 95215-2210.
A common edge case is filers with both a physical and a mailing address. If those differ, list the mailing address in Box 4 and the physical address in Box 5 (location of business), or correspondence will go to the wrong place.
A common mistake is using an old P.O. Box that has lapsed. The consequence is the refund warrant returns to CDTFA undeliverable, and reissue takes 8–12 weeks. The misconception is that an email address can replace a mailing address; CDTFA still mails statutory notices on paper under Government Code § 11440.20.
Box 5 — Period of Claim
This field asks for the dates that frame the refund period. Enter the from and to dates in MM/DD/YYYY format. Most filers use a calendar quarter or a calendar year. CDTFA allows monthly, quarterly, or annual claims under RTC § 60502, but you may not claim a period more than three years before the file date.
For example, Maria Lopez files her annual farm claim for 2025 and enters 01/01/2025 to 12/31/2025.
A common edge case is overlapping periods. If you already filed a claim for January–March, do not include those months again on an April–June claim, or the system flags it as a duplicate.
A common mistake is dating the period after the statute closes. The consequence is automatic denial under RTC § 60522, with no appeal path on timeliness. The misconception is that the statute runs from the date you bought the diesel — it runs from the date the tax was paid to the supplier, which is sometimes earlier.
Box 6 — Total Gallons Purchased (Tax-Paid)
This field asks for the total gallons of diesel you bought with California excise tax included during the claim period. Enter whole gallons; do not enter fractional gallons. Tie the number to your purchase invoices exactly.
For example, Maria Lopez, who burned diesel in her tractors and irrigation pumps, enters 18,420 gallons.
A common edge case is bulk-tank purchases that include both taxed and tax-exempt fuel. Separate them: only put tax-paid gallons in Box 6, and report the rest on the supplemental schedule.
A common mistake is using pump-meter readings instead of invoice gallons. The consequence is that the invoice total and the form total will not reconcile, and the examiner will reduce the refund. The misconception is that “more gallons claimed is fine if you have the receipts” — actually, over-claiming triggers an audit under RTC § 60581.
Box 7 — Gallons Used in Nontaxable Manner
This field asks for the gallons that qualify for the refund — those used off-highway, in exempt vehicles, or sold to exempt customers. Enter whole gallons. Support the number with your usage log, hour meter, or mileage records.
For example, Maria Lopez enters 17,850 gallons because almost all of her fuel was burned in unlicensed farm equipment.
A common edge case is mixed-use equipment such as a pickup truck used both on public roads and on the farm. Only the off-road portion qualifies, and you must keep a contemporaneous log under CDTFA Regulation 1432.
A common mistake is claiming 100% of pickup truck gallons as off-road. The consequence is partial denial and a 10% penalty under RTC § 60509. The misconception is that “farm use” automatically equals “off-road” — fuel used to drive farm vehicles on a public road to town is taxable.
Box 8 — Rate of Tax
This field asks for the per-gallon diesel tax rate in effect during the claim period. The rate adjusts every July 1 under the Road Repair and Accountability Act (SB 1). Enter the rate to four decimal places, for example $0.4490.
For example, Carlos Mendez applies the rate effective during his claim period, entering $0.4490 per gallon.
A common edge case is a claim period that straddles a rate change. Split the gallons by rate period, calculate each separately, and sum the refunds.
A common mistake is using last year’s rate. The consequence is a refund calculated too low or too high, and the examiner manually corrects it, delaying payment. The misconception is that all California fuel taxes are the same rate — gasoline, diesel, and aircraft jet fuel each have separate rates.
Box 9 — Refund Claimed
This field asks for the refund amount, calculated by multiplying Box 7 by Box 8. Enter the dollar amount to the cent. Use a calculator, not estimates.
For example, Maria Lopez multiplies 17,850 × $0.4490 = $8,014.65 and enters $8,014.65.
A common edge case is a claim that also seeks interest. Interest accrues only after CDTFA holds the claim more than a statutory period under RTC § 60511.
A common mistake is rounding to whole dollars. The consequence is a one-cent mismatch that triggers a re-keying flag. The misconception is that CDTFA “rounds in your favor” — it does not; the form must reconcile to the penny.
Box 10 — Use Type Code
This field asks you to identify the exempt use category. Codes include farm use, off-highway construction, exempt bus operations, train, marine, and U.S. government sale. Select one code per claim line; use multiple lines for multiple use types.
For example, Maria Lopez selects code 01 — Agricultural Use.
A common edge case is multi-use claims. If you have both farm use and government sales, split them across separate claim lines or use the supplemental schedule.
A common mistake is using the wrong code for refrigeration units (reefer fuel). Reefer use is its own category under CDTFA Regulation 1431; using the wrong code causes a partial denial.
The misconception is that “off-highway” and “off-road” are different categories. They are the same, but the form labels them “off-highway” — match the exact form label.
Box 11 — Supporting Schedules Attached
This field asks you to check boxes indicating which supporting schedules accompany the claim. Schedules include Schedule A (purchase detail), Schedule B (usage detail), and Schedule C (sales detail for DV claims).
For example, Maria Lopez checks Schedule A and Schedule B and writes 2 schedules attached in the margin.
A common edge case is electronic submissions. The online portal does not have checkboxes — it has upload slots — but you still must upload one PDF per schedule.
A common mistake is forgetting to attach Schedule A. The consequence is an automatic “Insufficient Documentation” letter that pauses the claim for 30 days. The misconception is that summary totals are enough; CDTFA requires invoice-level detail under Regulation 1430.
Box 12 — Declaration and Signature
This field asks you to sign under penalty of perjury that the claim is true and correct. Sign in blue or black ink, print your name, write your title (Owner, President, CFO), and enter the date in MM/DD/YYYY.
For example, Maria Lopez signs as Maria Lopez, Owner, 02/15/2026.
A common edge case is a signature by a paid preparer. The preparer must sign on the preparer line and provide their PTIN or CDTFA representative ID; the taxpayer still signs the claimant line.
A common mistake is leaving the date blank. The consequence is that CDTFA treats the claim as received on the postmark date, which may push the statute past the deadline. The misconception is that a typed name counts as a signature on paper claims — it does not; only an original ink signature satisfies RTC § 60521. Electronic claims through the portal use an e-signature PIN, which is valid under the Uniform Electronic Transactions Act.
Three Filled-Out Examples Using Real Scenarios
These three named filers show how the form behaves in the three most common 770 scenarios. Each table walks the same person through the form from top to bottom.
Scenario 1 — Maria Lopez, Almond Farmer
| Form Section | What Maria Enters |
|---|---|
| Box 1 — Claimant Name | Maria Lopez |
| Box 2 — CDTFA Account Number | SR FHB 98-765432 |
| Box 3 — FEIN or SSN | 123-45-6789 |
| Box 4 — Mailing Address | 2210 Orchard Lane, Fresno, CA 93722-3344 |
| Box 5 — Period of Claim | 01/01/2025 – 12/31/2025 |
| Box 6 — Total Gallons Purchased | 18,420 |
| Box 7 — Gallons Used Nontaxable | 17,850 |
| Box 8 — Rate of Tax | $0.4490 |
| Box 9 — Refund Claimed | $8,014.65 |
| Box 10 — Use Type Code | 01 — Agricultural Use |
| Box 11 — Schedules Attached | A and B |
| Box 12 — Signature | Maria Lopez, Owner, 02/15/2026 |
Scenario 2 — Carlos Mendez, Interstate Trucker
| Form Section | What Carlos Enters |
|---|---|
| Box 1 — Claimant Name | Mendez Trucking LLC |
| Box 2 — CDTFA Account Number | SR FHB 12-345678 |
| Box 3 — FEIN | 87-6543210 |
| Box 4 — Mailing Address | 4501 Charter Way, Stockton, CA 95215-2210 |
| Box 5 — Period of Claim | 07/01/2025 – 09/30/2025 |
| Box 6 — Total Gallons Purchased | 9,640 |
| Box 7 — Gallons Used Nontaxable (PTO + reefer) | 2,150 |
| Box 8 — Rate of Tax | $0.4490 |
| Box 9 — Refund Claimed | $965.35 |
| Box 10 — Use Type Code | 07 — Power Take-Off / Refrigeration |
| Box 11 — Schedules Attached | A, B, and IFTA reconciliation |
| Box 12 — Signature | Carlos Mendez, Manager, 10/20/2025 |
Scenario 3 — Sunrise Fuel Co., Ultimate Vendor (770-DV)
| Form Section | What Sunrise Enters |
|---|---|
| Box 1 — Claimant Name | Sunrise Fuel Co., Inc. |
| Box 2 — CDTFA Account Number | SR FHB 33-221100 |
| Box 3 — FEIN | 45-1122334 |
| Box 4 — Mailing Address | 900 Industrial Way, Bakersfield, CA 93308-1100 |
| Box 5 — Period of Claim | 04/01/2025 – 06/30/2025 |
| Box 6 — Total Gallons Sold Tax-Paid to Exempt Buyers | 54,200 |
| Box 7 — Qualifying Exempt-Sale Gallons | 54,200 |
| Box 8 — Rate of Tax | $0.4490 |
| Box 9 — Refund Claimed | $24,335.80 |
| Box 10 — Use Type Code | 09 — U.S. Government Sales |
| Box 11 — Schedules Attached | DZ sales schedule, exemption certificates |
| Box 12 — Signature | Janet Pierce, CFO, 07/25/2025 |
Beyond these three, two more named filers appear in this guide: Aisha Brown, a school district transportation manager filing on behalf of an exempt school bus fleet, and Marcus Hill, a construction company owner running unlicensed bulldozers and excavators. Each has slightly different field choices — Aisha uses use code 04 (school bus), and Marcus uses use code 03 (off-highway construction).
How to File the Completed Form
CDTFA accepts three filing channels for the 770 series. Choose the one that matches your record-keeping and your tolerance for waiting on a paper check.
Online filing through the CDTFA Online Services portal is the fastest channel. Log in, choose “File a Claim for Refund,” select the diesel fuel tax account, attach your schedules as PDFs, and submit. There is no filing fee. You can elect direct deposit, which usually arrives in 2–4 weeks after the examiner approves the claim. The system emails a confirmation number — save the PDF receipt as your proof of filing.
Filing by mail uses the address on the back of the form, typically CDTFA, Audit Determination and Refund Section, P.O. Box 942879, Sacramento, CA 94279-0035. There is no fee. Use Certified Mail with Return Receipt; the postmark establishes the filing date for statute-of-limitations purposes. Paper claims process in 6–10 weeks. Keep the certified mail green card as your proof of filing.
Filing in person is available at any CDTFA field office. There is no fee. The clerk date-stamps a copy of page 1 and returns it as your receipt — keep that stamped copy permanently. In-person filings still route to Sacramento for processing, so the timing matches mail.
Payment methods are not relevant for refund claims because no money flows to CDTFA on a 770 filing — money flows back to you. If CDTFA later issues a Notice of Determination reducing the refund and finding you owe tax instead, that notice comes with its own payment instructions through the Online Services portal accepting ACH, credit card, or check.
What Happens After You File
After CDTFA receives your form, the claim is logged and assigned a refund claim number, which arrives by mail or in your online inbox within 10 business days. The Audit Determination and Refund Section reviews the math, ties your gallons to your invoices, and verifies the use codes.
If everything ties, CDTFA issues an Approval Notice and either deposits the refund or mails a warrant within 2–8 weeks of approval. If something does not tie, you will receive a Request for Additional Information letter — you have 30 days to respond before the claim is denied for nonresponse under RTC § 60504.
A partial or full denial comes as a Notice of Action. You have 30 days to file a petition for redetermination under RTC § 60350, and another path to the Office of Tax Appeals if the redetermination is also adverse. Interest on approved refunds accrues at the rate set by RTC § 60511 only after CDTFA holds the claim past the statutory deadline.
A common misconception is that “no news is good news.” It is not. If you have not heard anything in 60 days, log into the online portal and check claim status. Silence often means the file is sitting on an examiner’s desk waiting for a missing schedule, and the clock on your statute of limitations is still running for the next quarter you have not yet claimed.
Mistakes to Avoid When Filling Out the Form
Each item below is a real reason CDTFA reduces or denies 770-series refund claims. Each consequence is specific, not generic.
- Filing on an outdated form revision — the claim is rejected as “Form Version Invalid” and must be refiled.
- Using the FEIN where the CDTFA account number is requested — the claim fails account lookup and is returned.
- Entering pump-meter gallons instead of invoice gallons in Box 6 — the totals do not reconcile and the refund is reduced.
- Claiming 100% off-road for a vehicle that ever touches public roads — partial denial plus a 10% penalty under RTC § 60509.
- Using last year’s diesel tax rate — refund is recalculated and delayed.
- Omitting Schedule A (purchase detail) — automatic 30-day suspension for insufficient documentation.
- Missing the 3-year statute of limitations in Box 5 — claim denied with no appeal on timeliness.
- Forgetting to date the signature — postmark date controls and may push you past the statute.
- Mixing fuel types (gasoline gallons mixed into a diesel claim) — refund is denied for the gasoline portion and may trigger an audit.
- Ignoring the U.S. government exemption certificate for DV claims — the exempt-sale gallons are reclassified taxable.
- Using the wrong use type code (for example, reefer fuel coded as off-highway) — partial denial.
- Mailing the claim without certified mail — no proof of timely filing if it gets lost.
Do’s and Don’ts
Do’s
- Do download the form from CDTFA’s official forms page every time, because revisions change without notice.
- Do reconcile Box 6 to invoice gallons before you sign, because reconciliation is the single biggest examiner check.
- Do use direct deposit through Online Services, because it cuts 4–6 weeks off the wait.
- Do keep purchase invoices for at least four years, because CDTFA can audit any claim within that window under RTC § 60581.
- Do split the claim across rate periods when July 1 falls inside, because the rate changes mid-year under SB 1.
- Do call 1-800-400-7115 the moment a question arises, because the call is free and shorter than a written exchange.
Don’ts
- Don’t round refund totals — pennies matter, because CDTFA’s match logic flags mismatches.
- Don’t fax the claim — CDTFA does not accept faxed refund claims, because original signatures are required.
- Don’t combine multiple periods into one claim — file one period per form, because mixed periods break statute tracking.
- Don’t use white-out — strike through, initial, and re-enter, because white-out raises tampering concerns.
- Don’t sign before the form is complete — CDTFA treats a signed-but-blank form as fraudulent, because the declaration covers the whole document.
- Don’t ignore the Request for Additional Information letter — respond within 30 days, because nonresponse means denial.
Pros and Cons of Filing on Your Own vs. With Help
Pros of filing pro se
- No professional fees, which can range from $250 to $2,000 per claim.
- Direct knowledge of your gallons and uses, which speeds up data entry.
- Faster turnaround for small claims, because there is no preparer middle step.
- Full control of correspondence with CDTFA.
- Easier to amend on your own timeline.
Cons of filing pro se
- Higher risk of math errors and use-code mistakes.
- Limited understanding of Regulation 1430–1432 nuances on mixed-use fuel.
- No representative to handle examiner pushback.
- Easy to miss the 3-year statute on older invoices.
- More time spent learning the form than a one-time filer wants to invest.
Pros of using a tax professional
- Familiarity with use codes and exemption rules.
- Faster turnaround on complex multi-rate or multi-entity claims.
- Audit defense if CDTFA pushes back.
- Knowledge of Office of Tax Appeals procedure if denial happens.
- Often catches federal off-highway credits on IRS Form 4136 you would have missed.
Cons of using a tax professional
- Fees reduce net refund.
- Slower onboarding for first claims.
- Less direct control of correspondence.
- Some preparers file on outdated forms.
- A bad preparer can sign a faulty claim that you remain liable for.
Paper Filing vs. Online Filing
| Filing Channel | Key Differences |
|---|---|
| Online via CDTFA portal | Free, 2–4 week refund, direct deposit available, instant filing receipt |
| Paper by mail | Free, 6–10 week refund, paper warrant only, certified mail recommended for proof |
Key Entities Involved
The California Department of Tax and Fee Administration (CDTFA) administers the Diesel Fuel Tax Law and processes every 770-series claim. The Office of Tax Appeals (OTA) hears appeals when redeterminations are denied. The California Franchise Tax Board (FTB) coordinates on identity matching and offsets against state income tax debts. The Internal Revenue Service (IRS) administers parallel federal off-highway refunds via Form 4136. The California Secretary of State anchors the legal name match for entity filers.
The governing statutes are RTC §§ 60501–60522, and the implementing regulations are Regulations 1430–1432. Publication 9, Tax-Free Sales of Fuel, explains the ultimate vendor rules; Publication 423 explains farm use; and Publication 117 explains refund mechanics across all CDTFA programs.
FAQs
Is the CDTFA-770 refund the same as the IRS off-highway refund?
No. The CDTFA-770 series refunds only the California state diesel tax. Federal off-highway refunds are filed separately on IRS Form 4136.
Can I file CDTFA-770-DU online?
Yes. The CDTFA Online Services portal accepts every 770-series form, supports direct deposit, and issues an instant filing receipt.
How long do I have to file a 770 refund claim?
Yes, there is a deadline. You have three years from the date the tax was paid to the supplier under RTC § 60522, with no exceptions for late discovery.
Do I write my legal name or DBA in Box 1?
Yes, write your legal name. The DBA goes on the line below, because the refund warrant is issued to the legal name only.
Should I enter my FEIN or my CDTFA account number in Box 2?
No, Box 2 is for the CDTFA account number only. The FEIN goes in Box 3, and mixing them causes an automatic account-not-found rejection.
Can I claim diesel I used in my pickup truck on the farm?
Yes, but only the off-road portion. Pickup gallons used to drive on public roads are taxable and cannot be in Box 7.
Do I round refund totals to the nearest dollar in Box 9?
No. Box 9 must reconcile to the cent. Rounding triggers a re-keying flag and slows the claim.
Can I file one form for two calendar quarters?
No. File one period per form, because mixed periods break CDTFA’s statute tracking and trigger a refile.
Is a typed signature valid on a paper 770?
No. Paper claims require an original ink signature under RTC § 60521. Only the online portal supports e-signatures.
Does CDTFA pay interest on my refund?
Yes, but only after CDTFA holds the claim past the statutory deadline under RTC § 60511. Interest does not accrue from the purchase date.
Can I amend a 770 claim I already filed?
Yes. File an amended 770 marked “AMENDED” at the top, with corrected gallons and a brief letter explaining what changed and why.
Do reefer (refrigeration unit) gallons qualify for a refund?
Yes. Reefer fuel is nontaxable because it does not propel the vehicle on a public road, but it must be coded with the reefer-specific use code, not generic off-highway.
What if my mailing address has changed since my last filing?
Yes, update it. File CDTFA-345, Notice of Business Change before submitting the refund, or the warrant goes to the old address.
Can a paid preparer sign on my behalf?
No. The preparer signs the preparer line, but you must still sign the claimant line, because the perjury declaration covers the taxpayer personally.
Related reading
- How to Fill Out California Form CDTFA-501-AB (w/Examples) + FAQs
- How to Fill Out California Form CDTFA-501-DG (w/Examples) + FAQs
- How to Fill Out California Form CDTFA-501-MV (w/Examples) + FAQs
- How to Fill Out California Form CDTFA-501-PS (w/Examples) + FAQs
- How to Fill Out California Form CDTFA-501-DD (w/Examples) + FAQs
- How to Fill Out California Form CDTFA-810-CTE (w/Examples) + FAQs