When an employee works across state lines, the localized work test for state income tax withholding tells you which single state receives the withholding. It runs as a strict four-tier hierarchy: localized service first, then base of operations, then place of direction and control, and finally the employee’s residence. You apply the tiers in order and stop the moment one produces a clear answer. Skipping ahead — jumping to residence because it looks easiest — is the classic way employers end up withholding for the wrong state and owing penalties in the state that should have received the money.1U.S. Department of Labor. UIPL 20-04 Localization of Work Provisions
The Four Tiers in Order
Each tier asks a single question. Move to the next only if the current one fails to point to a state.
Tier 1, localized service. Is the employee’s work performed entirely within one state, or is any out-of-state work merely incidental? If yes, that state gets the withholding. This tier resolves the vast majority of cases.
Tier 2, base of operations. If the work isn’t localized, look for the fixed location where the employee regularly starts assignments, keeps equipment, or returns after field work. If that base sits in a state where the employee performs some service, that state controls.
Tier 3, place of direction and control. If no base of operations exists in any state where work is performed, the analysis shifts to the location from which the employer manages the employee’s daily tasks: the office that assigns work, supervises performance, and holds authority over hiring and firing.
Tier 4, employee’s residence. Only if none of the first three tiers points to a state where the employee performs some work does the employee’s legal residence become the withholding state, and even then only if the employee does at least some work there.2Social Security Administration. Social Security Bulletin Volume 48 Number 10
The hierarchy exists precisely to prevent shortcuts. An employer who defaults to residence because it feels simplest risks withholding for the wrong state entirely.
What Counts as Incidental Work
Tier 1 turns on one word: incidental. An employee who works in a primary state 95% of the time and crosses the border for a client meeting or a weeklong training session is still localized in the primary state. The out-of-state activity is incidental because it is temporary, isolated, and lacks any permanent character.2Social Security Administration. Social Security Bulletin Volume 48 Number 10
No federal rule draws a bright line at a specific number of days. The test looks at the overall pattern. Is the out-of-state work a regular, recurring part of the job, or a one-off departure from the routine? A sales representative crossing into a neighboring state every other week is doing more than incidental work; that pattern suggests a job that genuinely spans two states and pushes the analysis to Tier 2. A software engineer flying to headquarters once a quarter for planning meetings is a clearer case of incidental travel. When in doubt, ask whether the employer expects the cross-border work to continue indefinitely. If it does, it probably isn’t incidental.
Nonresident Withholding Thresholds
Even when work in a second state is more than incidental, the employer may not owe withholding there immediately. Most states set a de minimis threshold — a minimum number of days worked or dollars earned — before nonresident withholding kicks in, and the thresholds vary widely.3Tax Foundation. Nonresident Income Tax Filing and Withholding Laws by State
A few examples show the range. Arkansas, Colorado, Maryland, and Oregon require withholding starting on the first day of nonresident work. Arizona and Hawaii give a 60-day window. Georgia triggers withholding after 23 days, or when earnings exceed $5,000, or when total compensation exceeds 5% of wages, whichever comes first. Ohio and Oklahoma use a $300 quarterly earnings threshold instead of counting days. Minnesota ties its threshold to an inflation-adjusted income figure, set at $15,300 for 2026.3Tax Foundation. Nonresident Income Tax Filing and Withholding Laws by State
Nine states have no individual income tax at all, so nonresident withholding is not an issue: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming. There is currently no federal law standardizing thresholds across the other states. Proposals such as the Mobile Workforce State Income Tax Simplification Act have circulated in Congress for years without being enacted, so employers with cross-border workers have to check each state’s rules individually.
Reciprocity Agreements That Override the Test
Reciprocity agreements can override the entire multi-state analysis. When an employee lives in one participating state and works in another, the employer withholds only for the employee’s home state, and the employee skips filing a nonresident return in the work state.
Roughly 30 reciprocal agreements exist across 16 states and the District of Columbia. The participating jurisdictions are Illinois, Indiana, Iowa, Kentucky, Maryland, Michigan, Minnesota, Montana, New Jersey, North Dakota, Ohio, Pennsylvania, Virginia, West Virginia, Wisconsin, and D.C.4Tax Foundation. State Reciprocity Agreements – Income Taxes Not every pair of these states has an agreement with every other; reciprocity applies only between specific partner states. An employee living in Pennsylvania and working in New Jersey is covered. The same employee working in Connecticut is not.
To use a reciprocity agreement, the employee typically files a certificate of non-residence with the employer, declaring residence in the partner state and directing withholding there instead of to the work state.5NFC Help. Certificate of Non-Residence for State Tax Without that certificate, the employer may default to withholding for the work state, leaving the employee to file a nonresident return to recover the money. If the employee changes duty stations, any existing certificate becomes void and a new one has to be filed for the new location.
Convenience of the Employer Rule for Remote Workers
Remote work created a wrinkle the localized work test was not designed to handle. Some states apply what is called the convenience of the employer rule. If an employee used to commute into that state and then switched to working remotely from home in another state, the original state can still tax the income, as long as the remote arrangement is for the employee’s own convenience rather than a business necessity imposed by the employer.
Five states enforce a full version of this rule: Alabama, Delaware, Nebraska, New York, and Pennsylvania. Connecticut and New Jersey apply retaliatory versions that target only residents of states that impose their own convenience rules. Oregon has a narrower version limited to nonresidents performing managerial functions. New York’s is probably the most litigated: state tax regulations treat all days worked outside New York as New York workdays unless the employee can demonstrate the out-of-state work was required by the employer, not merely allowed.
The practical impact is significant. An employee living in New Jersey who works remotely for a New York-based company may owe New York income tax on the full salary, even without setting foot in New York during the year. The employer would need to withhold for New York. That can produce withholding obligations to two states on the same wages, with the employee relying on a resident credit to avoid actually paying twice.
Avoiding Double Taxation and Fixing Wrong-State Withholding
When wages are taxed by both a work state and a home state, the employee is not stuck paying twice. Nearly every state with an income tax offers a resident credit: the home state reduces the tax owed by the amount already paid to the nonresident work state on the same income. The credit usually cannot exceed what the home state would have charged on that income, so employees in low-tax home states may see less relief than those in high-tax ones.
If an employer withheld taxes for the wrong state entirely — for a state where the employee never actually worked — the employee files a nonresident return in that state reporting zero income earned there and claims a refund of the withheld amount. The employee should notify the employer immediately so the error doesn’t repeat in the next pay period. States with reciprocity agreements simplify this: with the non-residence certificate on file, no nonresident return is needed at all.
Documentation That Backs Up the Analysis
Applying the test correctly depends on accurate data for every multi-state employee. At minimum, employers need the physical address of each work location, the employee’s legal residence, and the address of the office that directs the employee’s daily work. Residence is typically documented through a driver’s license, voter registration, or the employee’s own state withholding certificate.
Each state has its own withholding allowance certificate, the state-level equivalent of the federal W-4. These forms capture exemptions, residency status, and filing preferences that determine how much to withhold from each paycheck. Most state revenue department websites provide downloadable versions. A mismatch between the tier result and the form on file is one of the most common multi-state withholding errors.
Federal rules require employers to keep employment tax records for at least four years after the fourth-quarter return for that year is filed, and many states impose longer retention periods.6Internal Revenue Service. Employment Tax Recordkeeping Keep the localization analysis itself, not just the forms. If a state challenges the withholding decision years later, the documentation showing which tier applied and why is what defends it.