Construction Multi-State Tax: Nexus, Withholding, and Sales Tax on Materials When You Work Across State Lines

One job across the state line is enough. A crew on a job site is physical presence, and the federal shield most people have heard of, P.L. 86-272, protects only the solicitation of orders for tangible goods, so it never covers construction. From the first day of work you can expect five separate obligations in the new state: a nonresident income tax return on the share of profit earned there, payroll withholding for the days your crew works there, sales or use tax on the materials you install there, workers’ comp that actually covers that state, and a contractor’s license or registration before you start. Each has its own agency and its own penalty, and none of them knows or cares what you already pay at home.

Does one out-of-state job create income tax nexus?

Yes, almost always. Nexus is the connection that lets a state tax you, and employees or equipment on a job site inside its borders is the clearest connection there is. The only federal limit on state income tax, P.L. 86-272, bars a state from taxing a business whose only in-state activity is “the solicitation of orders … for sales of tangible personal property” that are approved and shipped from outside the state. Building, installing or repairing real property is a service performed on the ground, so the statute doesn’t reach it.

• 15 U.S.C. 381 protects, and only protects, “the solicitation of orders by such person, or his representative, in such State for sales of tangible personal property, which orders are sent outside the State for approval or rejection, and, if approved, are filled by shipment or delivery from a point outside the State.” A crew framing a building meets none of that.
• A shop that fabricates cabinets at home and ships them into another state may have a P.L. 86-272 argument on the goods. The moment its installers set foot on the site, the installation is a service and nexus attaches to that part regardless.
• Some states have day-count or dollar thresholds before a nonresident return is required, and they’ve been shrinking for years. Plan on nexus from day one, and treat any threshold you find as a filing convenience rather than a reason to skip registration.

Once nexus exists, the state will find the job. Building permits are public records, project owners file information returns, and a state that sees a permit with no matching withholding account or sales tax registration has its audit lead.

How do I file in two states without paying tax twice?

You file a nonresident return in the job-site state on the share of income sourced there, and your home state gives you a credit for that tax, capped at what it would have charged on the same income. So the net cost of an out-of-state job is the spread between the two states’ rates on the apportioned slice, and nothing more if both returns are filed and the credit is claimed. Skip the nonresident return and there’s no credit, only an assessment later.

• Sourcing follows the project. A contract to build in Virginia is Virginia revenue whatever state the office is in. Most states now weight apportionment entirely on sales; some still average sales, payroll and property, and a six-month job with a crew and an excavator on site pushes all three factors toward the job state.
• The home-state credit is statutory. North Carolina, for example, allows a resident “a credit against the taxes imposed by this Part for income taxes imposed by and paid to another state or country on income taxed under this Part,” limited to tax on income “derived from sources within that state” (N.C.G.S. 105-153.9). Most states with an income tax have a version, each with its own cap and paperwork; check the home state’s rule before you count on it.
• Entity type changes the paperwork. A sole proprietor or single-member LLC reports the out-of-state income on a personal nonresident return. An S-corp or partnership files an entity return in the job state, and some states then withhold on distributions to nonresident owners or let the entity file a composite return for them. Entity structure for contractors covers the choice; the multi-state filing count is one of its costs.

The math scales badly with the number of states. Each one is a separate return with its own apportionment schedule, and the home-state credit is computed state by state. The return preparation cost is real; budget it into the bid alongside the bond premium.

Do I have to withhold state income tax for a crew working out of state?

Usually from the first paycheck. When your employees earn wages in another state, that state generally wants tax withheld on the wages for the days worked there, and it wants you registered for a withholding account before you pay them. A few states have a de minimis floor, a reciprocity agreement with the employee’s home state, or both, and those are the only two ways out.

Obligation	What triggers it	Way out, if any
Nonresident income tax return	Income sourced to the job state	None; the home-state credit reduces the cost
Payroll withholding account	Wages paid for work performed in the state	State de minimis floor (Georgia: over 5% of wages or $5,000); reciprocity with the employee’s home state
State unemployment (SUTA)	Wages for services localized in the state	Localization rules assign each employee to one state
Workers’ comp	Employees working in the state	Home policy’s other-states coverage, reciprocity, or a new policy; none in the exclusive-fund states
Sales and use tax	Materials installed in the state	Tax already paid to the purchase state, up to the destination rate
Contractor license or registration	Any covered work above the state’s floor	Reciprocal licensing in a handful of states

• Georgia’s registration test is a useful model of a de minimis floor. Its Department of Revenue asks whether an employee can “attribute over 5% of their wages to Georgia, or more than $5,000”; below both, no payroll withholding registration is needed (Georgia adds that nonresident or miscellaneous withholding registration might still apply), above either, it is (Georgia DOR). A four-person crew on a six-month job clears that in the first month.
• Reciprocity is narrower than contractors hope. Virginia’s agreements cover only the District of Columbia, Kentucky, Maryland, Pennsylvania and West Virginia, and they exempt residents of those states “who have a limited presence in Virginia” (Virginia Tax). A North Carolina crew in Virginia gets no help from it; a Maryland crew does, as long as each worker is in Virginia 183 days or less, keeps no abode there, and has only wage income from Virginia.
• Split the wages by days. An employee who works 120 of 250 days in the job state has 48% of wages sourced there. Most payroll systems can handle a second state; many small-contractor setups aren’t configured for it until someone asks.
• Unemployment tax is assigned by employee. Federal FUTA is 6% of the first $7,000 of wages under IRC 3301 and 3306(b)(1), which drops to 0.6% for an employer that pays its state unemployment tax on time because the credit under IRC 3302 reaches 90% of the tax, and state unemployment tax generally follows each employee to the one state where the work is based, so a crew sent out for a single project usually stays on the home state’s account while a crew based in the job state doesn’t.

How does sales tax on materials work across state lines?

It depends on which of two roles the job state gives you, and most give you the first one. In an end-user state you pay sales tax when you buy the materials and charge the customer nothing, because improving real property is a service. In a contract-type state the answer flips with the contract: a lump-sum price makes you the consumer who pays tax at the supply house, while a separated contract makes you a retailer who buys tax-free on a resale certificate and collects tax from the customer on the materials.

• New York is the classic end-user state. Its Publication 862 says “a contractor must pay sales tax to its supplier when it purchases tangible personal property. It does not matter whether the tangible personal property will be used in performing a capital improvement or a repair, maintenance, or installation service.” Then the job type decides what the customer sees: on a capital improvement with a Form ST-124 in hand “no sales tax is required to be collected from the customer”; on a repair, maintenance or installation job “sales tax must be collected from the customer.”
• Texas is the contract-type state. The Comptroller’s guidance on new construction: “Under a lump-sum contract, you pay tax on all your supplies, materials, equipment, and taxable services when you buy them. You don’t charge your customer tax. Under a separated contract, you give your suppliers resale certificates instead of paying tax on materials you incorporate into the customer’s real property” (Texas Comptroller Publication 94-116). Under a separated contract, “the homebuilder is considered a retailer of the incorporated materials” and “must collect sales tax from the customer on the agreed contract price of all materials incorporated into the realty” (Publication 94-157). Repairing or remodeling nonresidential property in Texas is taxable in full, labor included.
• The failure mode is mixing the two. A contractor with a home-state resale certificate uses it to buy materials that get installed in an end-user state. The purchase state’s exemption was claimed wrongly, and the job state’s tax was never paid. The state auditor gets to pick which one to assess.

Getting a job’s role right means knowing three things before the first delivery: what state the materials are bought in, what state they’re installed in, and what kind of contract the customer signed. Track materials by job; the supplier’s address doesn’t decide the tax.

What’s use tax and why do auditors go after contractors?

Use tax is the sales tax the destination state charges when you bring in materials bought somewhere cheaper. Buy in a state with no sales tax or a lower rate, install in a state with a higher one, and you owe the difference to the state where the materials were consumed, with a credit for what the purchase state already collected. Contractors are the auditors’ favorite target because the pattern is so easy to spot: a home supply house account, invoices with the home-state rate, and a permit in a state that never saw a return.

The credit for tax already paid is statutory too. Massachusetts exempts sales “upon which the purchaser has paid a tax … under the laws of any state” and charges only the excess of its own rate over the other state’s (M.G.L. c. 64I, s. 7), which is why the New Hampshire purchase above owed the full 6.25% and a purchase in a 4% state would owe 2.25%, provided the 4% was legally due and that state gives Massachusetts buyers the same credit.

The fix is a habit. Every job gets a materials log by delivery location, the use tax differential is computed per job state, and the return goes in monthly or quarterly on whatever form the state uses. The money is a real project cost; the penalty and interest are the part you can choose not to pay.

Do I need separate workers’ comp and a license in each state?

Often both. A home-state workers’ comp policy covers other states only where its other-states section says so, and a few states won’t accept any private policy at all. Licensing is a separate gate, and in the strict states an unlicensed contractor can’t sue to collect and may have to hand the money back.

• Exclusive-fund states. Washington’s Department of Labor and Industries states it plainly: “Washington State law does not allow for private workers’ compensation coverage. You must purchase your coverage from L&I or be a certified self-insured employer,” and its reciprocal agreements with Montana and Nevada “do not include construction work” (Washington L&I). Ohio routes every private employer’s premium “into the state insurance fund” under R.C. 4123.35, with written agreements for work performed partly out of state under R.C. 4123.54. North Dakota requires its own coverage once an employee “earns or would have been expected to earn 25% or more” of annual wages in the state, or 25% of the employer’s payroll is for North Dakota work, or the employer hires anyone in North Dakota for North Dakota work (North Dakota WSI). North Dakota’s own all-states coverage for its employers “provides coverage for temporary and incidental exposures in all states except Ohio, Washington, and Wyoming” (North Dakota WSI, all states coverage), which is the exclusive-fund list in one sentence.
• Everywhere else, call the carrier before the crew mobilizes. Most policies will add the state to the other-states coverage and adjust the premium to that state’s rates. A gap means you’re personally paying the injured worker’s medical bills and lost wages, plus the state’s penalty for operating uninsured.
• Licensing. California requires a license for any job of $1,000 or more; the exemption in B&P 7048 covers only work where “the aggregate contract price for labor, materials, and all other items is less than one thousand dollars ($1,000)” and no building permit is required. Under B&P 7031(b), a customer who used an unlicensed contractor “may bring an action … to recover all compensation paid to the unlicensed contractor for performance of any act or contract.” Competent work is no defense. Other strict-license states have their own versions; a few regulate at the city level instead.
• Timing. A state license can take two or three months from application to issue. Apply when you start bidding in a new state, since a contract you’ve already won can’t wait.

What should I do next?

Before you bid out of state, confirm four things in writing: whether the state requires a license, registration or bond; whether your workers’ comp policy names that state; what registrations the revenue department wants for withholding and sales or use tax; and whether the city or county adds its own layer. Price all of it into the bid. If you’ve already worked in a state without doing any of this, the order of repair is the same: register, file the missing returns, then negotiate penalties from a position of having come forward.

• The insurance side of the same problem: construction insurance and bonding, including the other-states question and what a coverage gap costs.
• If the “subs” you send across the line are really employees, the withholding exposure doubles: worker classification penalties for contractors.
• Public work in another state usually means Davis-Bacon prevailing wages on top of the state layer.
• The accounting method and WIP schedule you carry into each state: contractor deductions and WIP accounting.
• Two parallel multi-state guides: e-commerce sales tax nexus for the economic-nexus rules that apply to goods, and restaurant sales tax for another industry where taxability turns on the transaction type.

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.