Arizona Does Not Mandate Underinsured Motorist Coverage
Arizona does not require underinsured motorist (UIM) coverage on any auto insurance policy. The state's minimum liability requirements are $25,000 per person, $50,000 per accident for bodily injury, and $15,000 for property damage. Uninsured motorist coverage is also optional. You can legally register and drive every vehicle in your household with only liability coverage and no UM or UIM protection.
Carriers must offer underinsured motorist coverage when you purchase a policy, but you can decline it. The declination must be in writing. Once you sign the rejection form, the carrier removes UIM from the policy. For a household insuring multiple vehicles on one policy, that single rejection applies to every car on the policy, not vehicle by vehicle.
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Get Your Free QuoteArizona Uninsured Motorist Rate
10.6%
More than one in ten drivers on Arizona roads carries no insurance. When an uninsured or underinsured driver hits one of your household's vehicles, your own UIM coverage is the only financial recovery path beyond the at-fault driver's assets.
Insurance Research Council, 2023
How the Rejection Rule Works for Multi-Car Policies
When you decline underinsured motorist coverage, the carrier documents your refusal with a signed rejection form. That form is a policy-level document, not a vehicle-level one. If you insure three cars on one policy and sign the UIM rejection, all three cars lose the coverage. You cannot accept UIM on two vehicles and reject it on the third within the same policy.
If you later add a fourth vehicle to the policy, the existing rejection remains in force. The carrier does not re-offer UIM at every vehicle addition unless you request it. To reinstate underinsured motorist coverage after rejecting it, you must contact the carrier and request the coverage be added back to the policy. The carrier will then re-rate the entire policy with UIM included.
Some households split vehicles across two policies to manage coverage differently. One policy might carry full coverage with UIM for daily-driven cars, while a second policy covers a rarely-driven vehicle with liability only and no UIM. That structure requires separate policies, not one shared policy with mixed coverage elections.
A single UIM rejection on a multi-car policy removes the coverage from every vehicle on that policy. You cannot pick and choose per car.
What Underinsured Motorist Coverage Actually Pays
Arizona's minimum liability requirement is $25,000 per person for bodily injury.
For households with multiple vehicles, the stacking question matters. Arizona allows stacking of UIM coverage only if the policy explicitly includes a stacking provision and you pay the higher premium for it. The coverage does not multiply by the number of vehicles unless you purchase a stacked policy. Most carriers in Arizona offer non-stacked UIM as the default and charge extra for stacking.
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How Adding or Removing Vehicles Changes UIM Elections
When you add a vehicle to an existing policy, the carrier re-rates the policy but does not automatically re-offer coverages you previously rejected. If you declined UIM when you bought the policy for your first two cars, adding a third car does not trigger a new UIM offer unless you ask. The rejection stays in place across all vehicles.
If you want UIM on the newly added vehicle, you must request it explicitly. The carrier will then add UIM to the entire policy and re-rate all three vehicles with the coverage included. You cannot add UIM to only the new vehicle while leaving the first two without it on the same policy.
Removing a vehicle from the policy does not change your UIM election. If you carried UIM on a three-car policy and sell one car, the remaining two vehicles keep the same UIM coverage at the same per-vehicle limit. The premium drops because you are insuring fewer vehicles, but the coverage structure stays the same unless you request a change.
Arizona Minimum Bodily Injury Limits
$25,000 / $50,000
Arizona requires only $25,000 per person and $50,000 per accident in liability coverage. A serious collision easily exceeds these minimums, leaving the at-fault driver's policy short and triggering your UIM coverage if you carry it.
Arizona Revised Statutes, Title 28
Comparing Carriers That Write Multi-Car Policies in Arizona
Most carriers writing multi-car policies in Arizona offer underinsured motorist coverage as an optional add-on. The premium varies by carrier, household driving history, and whether you select stacked or non-stacked UIM. Carriers that write standard and preferred-tier policies in Arizona include Allstate, American Family, CSAA, Farmers, Geico, Liberty Mutual, Mercury General, Nationwide, Progressive, State Farm, Travelers, and USAA. All of these carriers offer UIM as an option; none require it.
Non-standard carriers such as Acceptance Insurance, Bristol West, Dairyland, GAINSCO, Infinity, Kemper, The General, and National General also write multi-car policies in Arizona and offer UIM. If your household includes a driver with a DUI, points, or a suspended license, these carriers may be the only options willing to write the policy. UIM availability does not change based on risk tier, but the premium does.
Compare Carriers and Add UIM to Your Multi-Car Policy
Arizona does not require underinsured motorist coverage, but the state's 10.6% uninsured motorist rate and low minimum liability limits make UIM a decision worth evaluating for every household. If you declined UIM when you first bought your policy, you can request it at any time. The carrier will re-rate your policy with UIM included and give you a new premium. If you are adding a vehicle or combining two policies after a move or marriage, ask the carrier to quote the policy both with and without UIM so you can compare the cost difference.
Use the site's comparison tool to see which carriers write multi-car policies in Arizona and request quotes with UIM included. Compare the premium difference between non-stacked and stacked UIM if the carrier offers both. The tool connects you to carriers licensed in Arizona that write households with multiple vehicles.