Idaho Does Not Require Underinsured Motorist Coverage
Idaho does not mandate underinsured motorist coverage. The state requires only liability insurance—$25,000 per person for bodily injury, $50,000 per accident, and $15,000 for property damage—to register and legally drive a vehicle. Uninsured and underinsured motorist protection is optional.
When you insure two or more vehicles on one policy, the UM/UIM decision applies to the entire policy, not to individual cars. You accept or reject underinsured motorist coverage for every vehicle the policy covers in a single election. Most carriers require a signed rejection form if you decline.
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Get Your Free QuoteIdaho Uninsured Motorist Rate
6.4%
Approximately 6.4% of Idaho motorists drive without insurance, according to 2023 state insurance statistics. That rate translates to roughly one in sixteen drivers on the road carrying no liability coverage to pay claims they cause.
Idaho Department of Insurance, 2023
What Underinsured Motorist Coverage Actually Pays
Underinsured motorist coverage pays the difference between the at-fault driver's liability limit and your actual damages when their policy is too small to cover your medical bills, lost wages, or other injury costs.
The coverage does not pay for vehicle damage in Idaho—that falls under collision or uninsured motorist property damage, depending on the carrier and the policy structure. UM/UIM is strictly for bodily injury shortfalls.
When you add UM/UIM to a multi-vehicle policy, the per-person and per-accident limits you select apply to any covered driver in any covered vehicle.
Rejecting UM/UIM on a multi-car policy removes the protection from every vehicle and every driver the policy covers—you cannot decline it for one car and keep it for another.
How the UM/UIM Election Works on a Multi-Vehicle Policy
When you request a quote for a policy covering two or more vehicles, the carrier includes uninsured and underinsured motorist coverage by default in most cases. The quote shows the premium with UM/UIM included. If you want to decline, you sign a rejection form—typically a standalone document or an endorsement attached to the policy declarations—acknowledging that you understand the coverage and choose not to carry it.
The rejection is not permanent. You can add UM/UIM at renewal or mid-term by contacting the carrier and requesting the coverage. The carrier will re-rate the policy to reflect the additional protection, and the new premium applies from the effective date of the change forward. Removing UM/UIM mid-term works the same way—request the removal, sign the rejection form, and the carrier adjusts the premium.
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Why Households With Multiple Vehicles Often Keep UM/UIM
A household insuring multiple vehicles typically has higher total exposure than a single-car household. More drivers, more trips, more time on the road. The probability that one of your household's drivers will be hit by someone carrying only Idaho's $25,000 minimum increases with the number of vehicles and drivers you insure.
Medical bills from a serious collision can exceed $25,000 quickly. Emergency room treatment, surgery, physical therapy, and lost income during recovery add up. If the at-fault driver carries only the state minimum and your injuries cost $50,000, you face a $25,000 shortfall unless your own UM/UIM coverage fills the gap.
Idaho Minimum Liability Limits
$25,000 / $50,000
Idaho requires $25,000 per person and $50,000 per accident in bodily injury liability coverage. Drivers who carry only the minimum leave a gap when injuries exceed those amounts, and their own assets become the next target for unpaid claims.
Idaho Code Title 49, Chapter 12
Stacking and Per-Vehicle Limits
Idaho does not allow stacking of UM/UIM limits across multiple vehicles on the same policy. The per-accident limit applies once per collision, regardless of how many of your vehicles were involved.
Some states permit stacking, where each insured vehicle contributes its own UM/UIM limit to a single claim. Idaho is not one of them. The limits you select apply per occurrence, not per vehicle.
Compare Carriers That Write Multi-Vehicle Policies in Idaho
Nineteen carriers write auto insurance for Idaho households insuring multiple vehicles, including Allstate, American Family, Geico, Progressive, State Farm, and USAA. Each structures UM/UIM pricing differently, and the cost of adding underinsured motorist coverage to a multi-car policy varies by carrier, driver age, vehicle type, and location within the state.
Request quotes from at least three carriers with UM/UIM included at the limits you want, then compare the total premium. The difference in cost between accepting and rejecting UM/UIM is often smaller on a multi-vehicle policy than on a single-car policy because the per-vehicle incremental cost decreases as you add cars. Use Idaho Car Insurance Requirements' comparison tool to see carrier options that write policies covering your household's vehicles and the coverage structure you need.