Arizona mileage reimbursement law does not require private employers to pay employees for business use of a personal vehicle. The state sits with the majority that leaves the question to employer discretion. That does not mean employers can ignore mileage costs entirely: federal wage law, IRS tax rules, and your own written policies can each create enforceable obligations, and getting any of them wrong invites wage claims, tax liability, or breach-of-contract lawsuits.
No Private-Sector Reimbursement Mandate
Unlike California, Arizona has no statute requiring private employers to reimburse business expenses. The state’s labor code addresses mileage only for state officers and public employees, whose rates are set by the Department of Administration based on IRS guidelines and approved by the Joint Legislative Budget Committee. Private employers are not covered.
What governs private-sector reimbursement instead is a mix of employment contracts, handbooks, collective bargaining agreements, and federal law. If none of those sources creates an obligation, an employer is technically free to pay nothing for business miles. That freedom has real limits.
The FLSA Minimum Wage Floor
The most important limit is federal. Under Fair Labor Standards Act regulations, an employer violates the FLSA in any workweek when employee-borne expenses for tools, uniforms, fuel, or other job requirements cut into the minimum or overtime wages the employee is owed.1eCFR. 29 CFR 531.35 – Wage Payments Unreimbursed mileage follows the same rule. If gas and vehicle wear push an employee’s effective pay below the applicable minimum wage, the employer has a wage violation.
Arizona’s minimum wage for 2026 is $15.15 per hour, up from $14.70 in 2025 under the annual inflation adjustment in Arizona Revised Statutes 23-363.2Industrial Commission of Arizona. New 2026 Minimum Wage3Arizona Legislature. Arizona Code 23-363 – Minimum Wage The federal minimum of $7.25 still technically applies, but the higher state rate controls, so the FLSA analysis in Arizona uses $15.15 as the floor.
The risk concentrates in jobs that combine heavy driving with wages near the minimum: delivery drivers, home health aides, field technicians. An employee earning $16 or $17 an hour can easily spend enough on fuel in a heavy-driving week for net pay to slip under $15.15. Employers who pay nothing for mileage are betting no employee’s expenses will ever cross that line in any single workweek.
The IRS Standard Mileage Rate as a Benchmark
Because Arizona sets no rate, most employers default to the IRS standard mileage rate. For 2026, that rate is 72.5 cents per mile for business use, up 2.5 cents from 2025.4Internal Revenue Service. Notice 2026-10 – 2026 Standard Mileage Rates The IRS recalculates the figure annually based on a study of fixed and variable costs of operating a vehicle, including depreciation, insurance, fuel, maintenance, and tires.
No law requires private employers to use it. You can reimburse more, less, or use a different method entirely. But the rate carries weight for two reasons. First, it defines the maximum that can be reimbursed tax-free under a standard mileage method. Second, it functions as the accepted benchmark in employment disputes, so an employee paid substantially less has a stronger argument that unreimbursed costs are pulling wages below legal minimums.
Accountable Plans and the Tax Consequences of Getting It Wrong
How you structure reimbursement determines whether payments are tax-free or treated as taxable wages. The IRS draws a hard line between accountable and non-accountable plans.
For mileage reimbursements to be excluded from taxable income, the arrangement must qualify as an accountable plan under federal tax law. That requires three things: a business connection for the expense, adequate substantiation to the employer within a reasonable time, and the return of any excess reimbursement.5Office of the Law Revision Counsel. 26 USC 62 – Adjusted Gross Income Defined For mileage, substantiation means a contemporaneous log with destination, business purpose, date, and miles driven. The IRS treats 60 days after the expense as a reasonable substantiation deadline, and excess reimbursement must be returned within 120 days. Payments under a compliant plan stay off the W-2 and are not subject to income tax withholding, Social Security, or Medicare.6Internal Revenue Service. Fringe Benefit Guide – Publication 5137
Fail any of the three requirements and the entire payment becomes a non-accountable plan. The most common way employers stumble into this is a flat monthly car allowance with no mileage log. A $500 monthly “vehicle stipend” with no documentation requirement is taxable wages.6Internal Revenue Service. Fringe Benefit Guide – Publication 5137 The employer must withhold income tax, Social Security, and Medicare on the full amount and report it on the W-2, and the employer owes its share of payroll taxes on top. The flat stipend feels simpler, but a well-run accountable plan delivers more to the employee at lower total cost.
Which Trips Actually Count
Even employers with generous policies do not owe mileage for every trip. Under the Portal-to-Portal Act, ordinary travel between an employee’s home and regular workplace is not compensable and does not generate a reimbursement obligation.7Office of the Law Revision Counsel. 29 USC 254 – Relief From Liability and Punishment Reimbursable travel typically includes trips between work locations, client visits, off-site meetings, and deliveries. The line is whether the travel serves the employer’s business or simply gets the employee to and from a regular post.
Remote Workers and Home Offices
Remote work complicates the analysis. Under IRS Revenue Ruling 99-7, if an employee’s home office qualifies as their principal place of business, travel from home to any other work location in the same trade or business is deductible business travel regardless of distance or whether the destination is temporary or regular.8Internal Revenue Service. Revenue Ruling 99-7 If the home office does not qualify, travel from home to a regular work location remains personal commuting. Employers with hybrid staff should define in their policies which locations count as “regular” and when home-to-office travel qualifies.
Your Own Policy Can Create the Obligation
The absence of a state mandate does not eliminate legal exposure. Once you establish a reimbursement policy, you are bound by it. A written policy in a handbook, employment contract, or internal memo creates an enforceable obligation, and an employee denied reimbursement under a policy they relied on has grounds for a breach-of-contract claim.
Courts can also enforce verbal promises under promissory estoppel if an employee relied on a reimbursement commitment when accepting a job or incurring driving expenses. The promise does not need to be in writing; it needs to be specific enough that the reliance was reasonable.
Consistency matters too. Reimbursing some employees and not others doing substantially similar work invites discrimination claims. Reimbursing for years and then stopping without notice can support a claim that the practice created an implied contractual obligation. If you need to change a policy, communicate the change clearly and prospectively.
Liability When Employees Drive Personal Vehicles for Work
Mileage reimbursement is not only a wage issue. When employees drive personal vehicles on the job, the employer takes on liability many Arizona businesses underestimate.
Under respondeat superior, an employer can be held liable for an employee’s negligent driving if the accident occurs within the course and scope of employment. Ownership of the vehicle is irrelevant. What matters is whether the employee was performing work duties. Arizona courts look at how much control the employer exercised over the activity. An employee running a work errand or driving between job sites is generally within scope; an employee on a personal detour after hours generally is not.
Employers also face negligent entrustment claims if they let an employee with a poor driving record use a personal vehicle for work without checking that record. Hired and Non-Owned Auto (HNOA) insurance covers this gap, providing liability coverage above the employee’s personal auto policy when personal vehicles are driven for business. Standard commercial general liability policies typically exclude auto accidents, so without HNOA an employer may face a judgment with no insurance to pay it. Any Arizona employer that routinely asks employees to drive their own cars for work should carry HNOA coverage and confirm employees maintain adequate personal auto insurance.
How Reimbursement Disputes Get Resolved
Most disputes start internally through a supervisor or HR, and clear policies resolve most legitimate claims at that stage. If internal resolution fails, an employee who believes unreimbursed expenses caused a minimum wage violation can file a wage claim with the Industrial Commission of Arizona. The claim must be filed within one year of the date the wages were earned and cannot exceed $5,000.9Industrial Commission of Arizona. Wage Claim Instructions The Commission investigates and issues a determination based on evidence from both sides.10Industrial Commission of Arizona. Labor – Wage Claims – Frequently Asked Questions Claims over $5,000 go to small claims court or superior court instead.
Breach-of-contract claims over a written reimbursement policy bypass the Industrial Commission and go directly to civil court. They are not subject to the $5,000 cap and can include consequential damages if the employee can show the employer’s refusal caused additional financial harm. The strongest defense is a clear, consistently applied written policy with documented compliance. The weakest is no policy at all and ad hoc decisions.