Connecticut withholding tax requirements for employers come from Section 12-705 of the General Statutes: if you maintain an office or do business in Connecticut, you must deduct state income tax from every employee’s wages — resident and nonresident alike — in an amount that approximates their annual Connecticut tax liability as closely as practicable.1Justia. Connecticut Code Title 12 Taxation Chapter 229 Sec 12-705 – Withholding of Taxes From Wages and Other Payments Miss a deposit, use the wrong tables, or fail to collect a form, and penalties start at 10% of the unpaid tax plus 1% monthly interest, with personal liability waiting for whoever controls the money.
Register With DRS Before You Run Payroll
You cannot legally withhold until you are registered with the Connecticut Department of Revenue Services. New businesses register through the myconneCT portal. If you already have a DRS account for other state taxes, use the same portal to add withholding as an additional tax type.2Connecticut State Department of Revenue Services. New Employer Information Register separately with the Connecticut Department of Labor for unemployment taxes — the two agencies do not share registrations.
Collect a CT-W4 From Every Employee
Form CT-W4 tells you the employee’s filing status and the information you need to calculate withholding. Have every new hire complete one on day one, and let existing employees update theirs whenever their situation changes.
If an employee never turns one in, you do not get to estimate. Connecticut requires you to withhold at the highest marginal rate of 6.99% with no exemption allowance.3Connecticut Department of Revenue Services. Form CT-W4 Employee’s Withholding Certificate That is a punishing default, and the employee will feel it in every paycheck, so follow up persistently on missing forms.
When an Employee Claims Exemption
An employee who expects combined annual gross income of $24,000 or less can claim exemption from Connecticut withholding on the CT-W4. Military spouses can also claim an exemption under the federal Military Spouses Residency Relief Act using the same form. You are not required to independently verify that the employee qualifies, but you must have the completed CT-W4 on file. If DRS later finds the exemption was improper, the employee owes the tax — but accepting an obviously invalid form can draw questions back to you.
Calculate Withholding the Right Way
Connecticut gives you two calculation tools: the annual withholding tables, and the withholding calculation rules in Form TPG-211. There is no flat percentage method the way there is for federal supplemental wages — you use the tables or the rules.4Connecticut Department of Revenue Services (DRS). TPG-211, 2025 Withholding Calculation Rules
DRS updates both every year. The 2026 withholding tables took effect January 1, 2026.5Connecticut Department of Revenue Services. State of Connecticut 2026 Withholding Tables Running payroll off last year’s tables is one of the most common errors DRS sees. If you process payroll manually or through a small-shop system, confirm every January that the current year’s figures are loaded.
For bonuses, commissions, overtime, and other supplemental wages, use the DRS calculation rules to determine the state amount. Connecticut withholding is not required on compensation that is exempt from federal income tax withholding. The federal and state calculations run separately: at the federal level, supplemental wages can be withheld at a flat 22% (37% on amounts over $1 million in a calendar year),6IRS. Federal Income Tax Withholding Methods (Publication 15-T) but that flat rate does not carry over to Connecticut.
Deposit, File, and Reconcile on Schedule
DRS assigns every employer to a weekly, monthly, or quarterly deposit schedule based on payroll size. All payments must be made electronically through myconneCT.7Connecticut State Department of Revenue Services. 2026 – Withholding Tax Information Know your schedule before your first payroll, because missing a deposit date starts the penalty clock.
Regardless of deposit frequency, every employer files Form CT-941, the Connecticut Quarterly Reconciliation of Withholding, by the last day of the month after each quarter closes: April 30, July 31, October 31, and January 31.8Cornell Law School. Conn. Agencies Regs. 12-707-1 – Schedule for Filing Withholding Tax Returns and Payment of Taxes
By January 31 each year, give every employee a Form W-2 for the prior calendar year and file copies with DRS along with Form CT-W3, the annual reconciliation. Connecticut requires W-2 filings for every employee who received Connecticut wages, even if no Connecticut tax was actually withheld.9Connecticut State Department of Revenue Services. Form W-2 Electronic Filing Requirements
Report New Hires Within 20 Days
Each new employee must be reported to Connecticut’s Directory of New Hires within 20 days of the hire date. If you report electronically, you can instead send two monthly transmissions no less than 12 and no more than 16 days apart.10Office of the Law Revision Counsel. 42 USC 653a – State Directory of New Hires The report must include the employee’s name, address, and Social Security number, plus your business name, address, federal tax ID, and state tax ID.
Keep the Records
Connecticut regulations require you to keep every record needed to determine correct tax liability — CT-W4 forms, payroll records, amounts withheld, amounts remitted — for at least three years from the extended due date of the return, available to DRS on request.11Connecticut eRegulations. Sec. 12-2-12 – Recordkeeping and Record Retention The IRS requires employment tax records for at least four years after you file the fourth-quarter return for the year.12Internal Revenue Service. Employment Tax Recordkeeping Keep everything for four years and you satisfy both.
Out-of-State Employees Are a Trap
Connecticut has no reciprocal income tax agreements with any other state. Not New York, not Massachusetts, not Rhode Island.13Connecticut General Assembly. State Income Taxes on Income Sourced to Other States A nonresident who works in Connecticut generally owes Connecticut tax on wages earned here, and may owe tax in their home state as well.
Connecticut also applies a “convenience of the employer” rule, but only reciprocally. If a nonresident employee of a Connecticut employer works remotely from a state that itself imposes a convenience rule — New York is the common example — Connecticut sources those wages back to Connecticut unless the remote arrangement exists because of the employer’s necessity rather than the employee’s preference.14Connecticut General Assembly. Convenience of the Employer Rule The rule does not reach employees in states without their own convenience framework.
Any time you hire someone across state lines or an existing employee moves, review your withholding duties in both states before the next payroll runs. The alternative is underpaying one state and double-withholding on the employee.
What Non-Compliance Costs
Section 12-735 sets Connecticut’s penalty structure, and the numbers accumulate quickly.
Pay the tax shown on your return late, and DRS adds a penalty of 10% of the unpaid amount, plus interest of 1% per month or fraction of a month from the original due date until payment.15FindLaw. Connecticut General Statutes Title 12 Taxation 12-735 – Failure to Pay Tax or Make Return On a $10,000 shortfall, that is $1,000 the first day and $100 for every month you stay behind.
Fail to file a required return within three months of the deadline and the DRS Commissioner can prepare one for you using the best available information. The penalty is 10% of the tax or $50, whichever is greater, plus the same 1% monthly interest.
Personal Liability
Under Section 12-736, DRS can assess any person responsible for collecting, accounting for, or remitting withholding taxes a penalty equal to the full amount evaded, uncollected, or unpaid.16Connecticut State Department of Revenue Services. Can I Be Held Personally Liable for Payment of Business Taxes Officers, directors, and anyone with authority over company finances can be personally liable — the corporate shield does not protect them — and criminal penalties can apply on top. The IRS has a parallel Trust Fund Recovery Penalty for federal employment taxes, assessable against any responsible person who willfully fails to collect or pay, with “willful” interpreted broadly to include paying other creditors when you knew taxes were owed.17Internal Revenue Service. Employment Taxes and the Trust Fund Recovery Penalty (TFRP)
If a Penalty Is Assessed
You can request a penalty waiver from DRS if the violation resulted from reasonable cause rather than neglect or intentional disregard. Submit Form DRS-PW through myconneCT, by fax, or by mail.18Connecticut State Department of Revenue Services. Penalty Waiver Request, Offer in Compromise or Protest Two conditions trip people up: you must pay all tax and interest before DRS will consider the request, and interest itself cannot be waived. Waivers are also unavailable for penalties resulting from an audit.
If you disagree with an assessment outright, file a formal protest within 60 days of the notice. DRS reviews internally and may hold a hearing. If the decision goes against you, you have one month to appeal to the Connecticut Superior Court in the New Britain Judicial District, with further appeals available up through the Connecticut Supreme Court.19Connecticut General Assembly. Tax Appeal Process The employers who do well in protests are the ones who can produce complete payroll records, CT-W4 forms, and deposit histories showing good-faith compliance — which is the same documentation your three-and-four-year retention schedule is already building.