How to Fill Out and File SC Form WH-1605: Due Dates, Submission, and Penalties

South Carolina Form WH-1605 is the quarterly withholding tax return that employers and other withholding agents use to report state income tax withheld during the first, second, or third quarter of the calendar year. Each return is due on the last day of the month after the quarter ends, and you file it through MyDORWAY or by mail to the South Carolina Department of Revenue (SCDOR). The fourth quarter is not filed on this form — it uses Form WH-1606, which also serves as the annual reconciliation.¹

Who Has to File

Any employer or withholding agent with an employee earning wages in South Carolina must register for a withholding account and file quarterly returns.² This applies even without a physical presence in the state. A single employee working in South Carolina triggers the obligation once the employee’s wages are expected to reach $1,000 or more during the year.³

File a WH-1605 even if you withheld nothing during the quarter. An active withholding account that goes quiet without a return triggers delinquency notices. If your business permanently stops paying wages, close the account through MyDORWAY or note the closure on your paper return. SCDOR no longer accepts separate paper closing forms.⁴

Quarterly Due Dates

The WH-1605 covers only the first three quarters:¹

First quarter (January–March): April 30
Second quarter (April–June): July 31
Third quarter (July–September): October 31

South Carolina deposits are made on the same schedule as your federal deposits, so the quarterly return deadline does not push back a deposit that was already due earlier in the quarter. The fourth quarter (October–December) uses Form WH-1606, due January 31 of the following year.⁵

Filling Out the Form

The WH-1605 is a short form: identifying information at the top and six numbered lines. Before you start, pull your payroll records for the quarter, your SC Withholding File Number, and records of any deposits you’ve already sent to SCDOR during those three months.

Header Information

Enter your business name and address, your federal employer identification number (FEIN) or Social Security number, and your SC Withholding File Number. The file number was assigned when you registered through MyDORWAY.² If you’re logging into MyDORWAY to file, you’ll also need a Letter ID or a copy of your last return.

Line 1: Total Tax Withheld

Enter the total South Carolina income tax you withheld from all sources during the quarter. Pull this from your payroll system; it should match the sum of state income tax withheld across every paycheck issued in the quarter. Do not enter negative numbers.¹

Line 2: Deposits Already Made

Add up every withholding payment you sent to SCDOR during the quarter and enter the total here. If you deposit monthly or more often, this will combine several payments.

Lines 3 and 4: Refund or Tax Due

If Line 2 is larger than Line 1, enter the difference on Line 3 as a refund and skip the rest. If Line 2 is smaller than Line 1, enter the shortfall on Line 4 as tax due.¹

Lines 5 and 6: Penalty, Interest, and Total Payment

Line 5 is for penalty and interest, which apply only if your return or payment is late. MyDORWAY has a calculator that will compute these amounts. Line 6 is the total payment: Line 4 plus Line 5. All cent fields take two decimal places (.00 through .99).

How to Submit

MyDORWAY

SCDOR recommends filing electronically through MyDORWAY at mydorway.dor.sc.gov. The form’s own instructions call it “the fastest, easiest way to file this return and make your payment.”¹ You can enter the data directly or upload withholding files. Log-in requires your FEIN or SSN, your SCDOR File Number, and either a Letter ID or a copy of your most recent return.

Paper Filing

If you file on paper, use the address that matches your situation:¹

Balance due: SCDOR, Withholding, PO Box 100161, Columbia, SC 29202
Refund or zero tax: SCDOR, Withholding, PO Box 125, Columbia, SC 29214-0004

The postmark date determines timeliness. Certified mail is worth the small extra cost if you’re close to the deadline. Paper returns take longer to process than electronic ones.

Amending a WH-1605

If you catch an error after you’ve filed, submit a corrected version with the “AMENDED Return” box checked. On Line 1, enter the corrected quarterly withholding total. On Line 2, include the amount you paid with the original return along with any other deposits made during the quarter.¹ The rest of the form works the same way, and the amended calculation will show whether you owe more or are due a refund for the corrected quarter.

Penalties for Late Filing or Payment

South Carolina has two separate penalty tracks, and they can stack:

Failure to file: 5% of the tax due for the first month the return is late, plus 5% for each additional month or partial month, up to 25%.⁶
Failure to pay: 0.5% of the unpaid tax per month or partial month, also capped at 25%.⁶

Interest also accrues on any unpaid balance from the original due date until paid in full, at a rate SCDOR sets using the IRS underpayment rate.⁶ A zero return filed on time carries no penalty; a missing return triggers SCDOR’s automated delinquency process. If you have no payroll activity, still file.

What to Keep After You File

The IRS requires employers to keep employment tax records for at least four years after the tax becomes due or is paid, whichever is later.⁷ That covers W-2 copies, deposit receipts, payroll ledgers, and filed WH-1605 returns. Holding records at least four years also protects you against most state assessment windows. Save your MyDORWAY confirmations with your paper files; they’re your proof of timely filing if SCDOR ever asks.

1
South Carolina Department of Revenue. WH-1605 South Carolina Withholding Tax Return
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South Carolina Department of Revenue. Apply for a Business Tax Account
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South Carolina Legislature. South Carolina Code 12-8 – Income Tax Withholding
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South Carolina Department of Revenue. Withholding Forms
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South Carolina Department of Revenue. WH-1606 South Carolina Withholding Fourth Quarter and Annual Reconciliation Return
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South Carolina Legislature. South Carolina Code 12-54 – Taxes, Administrative and Procedural Provisions
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Internal Revenue Service. How Long Should I Keep Records?