Why this matters to owner-operators and fleets

South Carolina’s Department of Revenue (SCDOR) keeps a single, searchable clearinghouse of tax guidance—its Advisory Opinion Search. It’s where the agency posts Information Letters, Revenue Rulings, and Procedures that can move filing dates, clarify rates, and explain exemptions. That page also spells out that advisory opinions remain in effect until a statute, regulation, court decision, or a newer opinion changes them—critical context when you’re budgeting, buying equipment, or timing filings.

What’s new on the page—and why it’s a useful dashboard

Recent listings include pandemic-era examples like SC Information Letter 20-8 (state income tax relief expanded in step with IRS Notice 2020-23) and SC Information Letter 20-9 (a licensing deadline extension), illustrating how SCDOR uses these notices to quickly adjust deadlines during emergencies. For motor carriers, these notices are a reminder to check the advisory index first whenever a disaster or emergency is declared.

Three examples that hit trucking operations

Income and withholding deadlines can shift after disasters. In the wake of Hurricane Helene, SCDOR postponed several state return and payment due dates that originally fell between September 25, 2024 and May 1, 2025; those items were moved to May 1, 2025. That included 2024 individual and business income tax returns and certain quarterly withholding filings (for example, returns originally due October 31, 2024; January 31, 2025; and April 30, 2025). If your shop uses South Carolina withholding or files a pass-through return, these adjustments mattered to cash flow planning.
Motor Fuel User Fee basics—and how relief has looked in the past. South Carolina’s Motor Fuel User Fee is assessed when fuel is removed from the terminal or imported, with diesel included under “special fuel.” As of July 1, 2022, the user fee is $0.28 per gallon. During COVID-19, SCDOR temporarily pushed certain state tax due dates (including motor fuel user fee filings due in April–May 2020) to June 1, 2020—an example of how the agency carves out non-income taxes during emergencies. Monitor the advisory opinions if another event affects filing windows.
Equipment purchases: Max Tax vs. IMF. SCDOR’s Max Tax guidance explains which items are capped under the state’s maximum sales and use tax and notes that items subject to South Carolina’s Infrastructure Maintenance Fee (IMF)—generally motor vehicles, motorcycles, trailers, and semitrailers pulled by a truck tractor—are exempt from Max Tax because IMF is paid to SCDMV instead. Understanding which bucket your purchase falls into (Max Tax or IMF) can change your out-the-door cost model for tractors, trailers, or shop equipment.

How to use SCDOR’s Advisory Opinion Search in two minutes

Filter by Tax Category. Start with “Motor Fuel User Fee,” “Sales & Use Tax,” and “Withholding” for the most trucking-relevant items.
Set Year and Status. Narrow to 2024–2025 and “Current” to see live guidance, then widen if you need historical context.
Scan the Citator and Index. The quarterly Citator shows whether a new opinion modifies or supersedes an older one; the Advisory Opinion Index groups frequently updated letters like interest rates and local tax charts.
Bookmark disaster relief and sign up for alerts. When severe weather or other emergencies hit, SCDOR posts relief details and often coordinates with IRS actions (e.g., COVID-19 relief under IRS Notice 2020-23). Subscribe to SCDOR updates to catch deadline changes quickly.

Need a quick history check? Two instructive examples

COVID-19 income tax relief (April 13, 2020). SC Information Letter 20-8 extended state income tax filing/payment relief to July 15, 2020, and clarified that other SCDOR-administered taxes (like sales and use, withholding, and motor fuel user fees) were covered by a separate June 1, 2020 relief window. This is a template for how SCDOR slices relief by tax type.
License renewals (May 18, 2020). SC Information Letter 20-9 extended the renewal deadline for certain coin‑operated device licenses to July 31, 2020—proof that licensing dates can shift through Information Letters, too.

Bottom line for trucking

When storms, pandemics, or legislative tweaks change the rules, SCDOR’s Advisory Opinion Search is the fastest way to confirm what’s changed—and what hasn’t—across income, withholding, motor fuel user fee, and sales/use taxes that hit your business. Assign someone to check it monthly (and after any disaster declaration), save relevant letters to your compliance binder, and coordinate with your CPA so cash, compliance, and equipment plans stay in sync.

Sources Consulted: South Carolina Department of Revenue; Internal Revenue Service.

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This article was prepared exclusively for truckstopinsider.com. For professional tax advice, consult a qualified professional.