Arizona has no law requiring private employers to reimburse employees for mileage driven in a personal vehicle for work. That places Arizona among the majority of states that leave the question to employer discretion. But Arizona mileage reimbursement law is not just the state statute: federal wage rules, IRS tax treatment, and any policy you put in writing can each turn a discretionary payment into a legal obligation.
No State Mandate for Private Employers
California and a handful of other states require employers to reimburse all necessary business expenses, mileage included. Arizona does not. The state’s labor code addresses mileage reimbursement only for state officers and public employees, whose rates are set by the Department of Administration based on IRS guidelines and subject to approval by the Joint Legislative Budget Committee. Private-sector employers fall outside that statute.
In practice, reimbursement for Arizona’s private workforce is governed by employment contracts, handbooks, collective bargaining agreements, and federal law. If none of those creates an obligation, an employer can technically pay nothing for business miles. That freedom has real limits.
The Federal Minimum Wage Floor
Federal regulations say an employer violates the Fair Labor Standards Act 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 counts. If gas and vehicle wear push effective pay below the minimum, the employer has a wage violation on its hands.
Arizona’s minimum wage for 2026 is $15.15 per hour, up from $14.70 in 2025 under the inflation adjustment required by Arizona Revised Statutes 23-363.2Industrial Commission of Arizona. New 2026 Minimum Wage The rate is recalculated each year based on the Consumer Price Index through August of the prior year.3Arizona Legislature. Arizona Code 23-363 – Minimum Wage The federal minimum of $7.25 still applies in Arizona, but the state rate is more than double, so the state rate controls. The FLSA analysis uses $15.15 as the floor.
Where employers get caught: a delivery driver, home health aide, or field technician earning $16 or $17 an hour can easily spend enough on gas in a heavy-driving week for net pay to dip below $15.15. The risk is highest for employees who drive extensively and earn near the minimum. Paying nothing for mileage is a bet that 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, the 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 it each year from a study of fixed and variable vehicle operating costs, including depreciation, insurance, fuel, maintenance, and tires.
No law requires private employers to use this rate. You can pay more, less, or use a different method. The rate matters for two reasons: it caps the amount that can be reimbursed tax-free under the standard mileage method, and it functions as the default benchmark in wage disputes. An employee who receives substantially less than the IRS rate has a stronger argument that unreimbursed costs are dragging wages below legal minimums.
FAVR as an Alternative
Employers with large driving workforces sometimes use a Fixed and Variable Rate plan instead of flat cents-per-mile. A FAVR plan combines a periodic fixed payment (for insurance, depreciation, and registration) with a variable per-mile payment (for fuel and maintenance). Properly structured, the allowance is not taxable.
The IRS requires each employee to substantiate at least 5,000 business miles per year, or 80 percent of the plan’s projected annual mileage, whichever is greater. The plan must include at least five employees, cannot cover mostly management, and the employee’s vehicle must meet cost thresholds tied to a “standard automobile” defined in the plan.5Internal Revenue Service. Internal Revenue Bulletin 2019-49 – Revenue Procedure 2019-46 A plan that fails any requirement loses tax-free status, and the full reimbursement becomes taxable wages.
How You Pay Determines the Tax Treatment
Whether reimbursements are tax-free or treated as wages depends on how the plan is structured. The IRS draws a hard line between accountable plans and non-accountable plans.
Accountable Plans
To exclude reimbursements from taxable income, the arrangement must qualify as an accountable plan: the expense must have a business connection, the employee must adequately substantiate it within a reasonable time, and any excess reimbursement must be returned.6Office of the Law Revision Counsel. 26 USC 62 – Adjusted Gross Income Defined
For mileage, adequate substantiation means a contemporaneous log showing destination, business purpose, date, and miles driven. The IRS treats 60 days after the expense as a reasonable substantiation window and 120 days as the deadline for returning excess payment. Employers can set tighter deadlines. When all three conditions are met, the payments stay off the W-2 and are not subject to income tax withholding, Social Security, or Medicare.7Internal Revenue Service. Fringe Benefit Guide – Publication 5137 Records should be kept at or near the time of travel; reconstructed logs invite trouble.4Internal Revenue Service. Notice 2026-10 – 2026 Standard Mileage Rates
Flat Stipends Are Taxable Wages
If an arrangement fails any of the three requirements, it is a non-accountable plan and the whole payment is taxable. The most common misstep is a flat monthly car allowance with no mileage logs. A $500 monthly “vehicle stipend” with no documentation requirement is wages, full stop.7Internal Revenue Service. Fringe Benefit Guide – Publication 5137 The employer withholds income tax, Social Security, and Medicare on the full amount, reports it on the W-2, and pays its share of payroll taxes on top. The employee nets less; the employer pays more. A properly run accountable plan with mileage tracking delivers more value to the employee at lower total cost.
What Travel Counts as Reimbursable
Even generous policies do not cover every trip. The key split is between commuting and business travel.
Under the Portal-to-Portal Act, ordinary travel between home and a regular workplace is not compensable work time and generates no reimbursement obligation.8Office of the Law Revision Counsel. 29 USC 254 – Relief From Liability and Punishment Reimbursable travel typically includes trips between work locations, visits to client sites, off-site meetings, and deliveries. The question is whether the drive serves the employer’s business or simply gets the employee to and from a regular post.
Remote Workers
Remote work complicates this. Under IRS Revenue Ruling 99-7, if an employee’s home office qualifies as the principal place of business, travel from home to any other work location in the same trade or business is deductible business travel, whatever the distance.9Internal Revenue Service. Revenue Ruling 99-7 If the home office does not qualify, travel from home to a regular work location is still personal commuting.
For hybrid employees who occasionally drive to a company office, the distinction decides whether the trip is business mileage. Spell out in your policy which work locations are “regular” and when home-to-office travel qualifies.
When a Policy Becomes a Legal Obligation
Once you adopt a reimbursement policy, you are bound by it. A written policy in a handbook, employment contract, or internal memo creates an enforceable obligation. An employee denied reimbursement under a policy they relied on has grounds for a breach-of-contract claim.
Verbal promises can also bind an employer through promissory estoppel if an employee reasonably relied on them when accepting the job or incurring expenses. The promise does not need to be written; it needs to be specific.
Consistency matters as much as the written word. Reimbursing some employees but not others doing similar work invites discrimination claims. Reimbursing for years and then stopping without notice can give rise to claims that the practice created an implied obligation. Change your policy prospectively, and communicate the change clearly.
Liability When Employees Drive Their Own Cars
Mileage is not just a wage issue. When employees drive personal vehicles for work, the employer takes on liability most Arizona businesses underestimate.
Under respondeat superior, an employer can be held liable for an employee’s negligent driving if the accident happens within the course and scope of employment. Company car or personal car, it does not matter. What matters is whether the employee was performing work duties. Arizona courts look at the degree of control the employer exercised over the activity. An employee running a work errand or driving between job sites is within scope; an employee on a personal detour after hours generally is not.
Employers also face potential negligent entrustment claims if they allow an employee with a poor driving record to use any vehicle for work without checking that record. The duty of reasonable care does not turn on who owns the car.
Hired and Non-Owned Auto (HNOA) coverage fills exactly this gap, providing liability coverage above the employee’s personal auto policy when a personal vehicle is used for business. Standard commercial general liability policies typically exclude auto accidents, so without HNOA, a judgment may land on the employer with no insurance behind it. Any Arizona employer that routinely asks employees to drive their own cars for work should carry HNOA coverage and verify that employees maintain adequate personal auto insurance.
Resolving a Reimbursement Dispute
Most legitimate disputes get resolved through an internal complaint to a supervisor or HR when the employer has a clear policy and follows it.
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 $5,000.10Industrial Commission of Arizona. Wage Claim Instructions The Commission investigates and issues a determination based on the evidence from both sides.11Industrial Commission of Arizona. Labor – Wage Claims – Frequently Asked Questions Claims above $5,000 must go to small claims or superior court.
Breach-of-contract claims over a written reimbursement policy bypass the Industrial Commission and go straight to civil court. These claims are not subject to the $5,000 cap and can include consequential damages where the employee can show the refusal caused additional financial harm. The strongest employer defense is a clear, consistently applied written policy with documented compliance. The weakest position is no policy at all and ad hoc reimbursement decisions.