Before the claim
What has to happen at the scene before you can file
A UM/UIM claim starts with the same documentation as any accident claim, plus one extra requirement if the other driver cannot be identified. Call 911 and request that an officer respond. The CHP or local police department report number is the primary document your own carrier uses to verify the at-fault driver's insurance status, or to confirm a hit-and-run. Do not skip the report even if the other driver insists the damage is minor or asks to settle privately. Photograph all vehicle damage, the full location, and any visible injuries, and collect names and phone numbers of independent witnesses immediately, since their account often becomes the deciding factor in a hit-and-run UM claim.
If the other driver fled the scene, California's UM statute requires physical contact between the fleeing vehicle and yours (or you, if you were on foot) for the claim to qualify, and carriers routinely require same-day police reporting for a hit-and-run. Waiting days to report creates a carrier argument that the delay prevented investigation.
Step 1
Notify your own carrier, ideally within 24 hours
Report the accident to your own insurance company as soon as reasonably possible, ideally within 24 hours, even before you know whether UM or UIM will end up applying. California's notice-prejudice rule (Insurance Code §554) means a carrier must show it was substantially prejudiced by late notice before it can deny a claim on that basis alone, but prompt reporting removes the argument entirely and starts the claim moving.
Step 2
Determine which claim type applies: UM or UIM
If the at-fault driver is identified and has no insurance at all, your carrier processes a standard UM claim directly: they pay your medical bills, lost wages, and pain and suffering up to your UM limit. If the at-fault driver is identified and insured, but their liability limits are not enough to cover your damages, the claim runs as UIM instead. UIM only activates once the at-fault driver's liability policy is fully exhausted; your UIM carrier needs proof of that payout, usually the at-fault carrier's settlement letter, before they pay the remaining gap. This means a UIM claim generally cannot move to resolution until the third-party liability claim against the at-fault driver settles first.
Step 3
What your own adjuster actually asks for
Once the claim is open, expect your carrier's adjuster to request a fairly consistent set of documentation:
- The police report number and a copy of the report once it is available, which typically takes several days to a couple of weeks after the accident.
- A recorded or written statement describing how the accident happened, in your own words. Answer accurately and stick to what you observed; you are not required to speculate about things you did not see.
- Medical records and bills connecting your treatment directly to the accident, including the initial emergency room or urgent care visit and any follow-up care.
- Proof of lost wages if you missed work, typically a letter from your employer confirming missed days and your pay rate, or pay stubs showing the gap.
- Photos and any independent witness contact information you collected at the scene, particularly important for a hit-and-run claim where corroboration beyond your own statement is often required.
- Confirmation of the at-fault driver's insurance statuswhere available. If the at-fault driver's own carrier issued a denial letter (for example because that driver misrepresented their license status or let their policy lapse before the accident), that denial letter is what your UM carrier needs to treat the at-fault driver as uninsured for your claim.
Step 4
How UM/UIM interacts with your health insurance
Health insurance and UM/UIM cover different things and typically both come into play after a serious injury. Health insurance pays your medical bills as treatment happens, usually subject to a deductible and coinsurance. UM/UIM pays medical bills, lost wages, and pain and suffering, none of which health insurance covers beyond the medical bills themselves. The two do not simply stack without adjustment: your health insurer typically asserts a right of reimbursement, called subrogation, against any UM/UIM settlement you receive for the portion of your medical bills the health insurer already paid. In practice this means your UM/UIM settlement is often reduced by what you already collected through health insurance, though the net result to you is usually still meaningfully higher than health insurance alone, since UM/UIM adds lost wages and pain and suffering that health insurance never covers. Whether your specific health plan asserts subrogation, and how much, depends on your plan's terms; ask your health insurer directly if a subrogation letter has not arrived yet.
Step 5
The property damage side runs separately
UM Property Damage (UMPD) covers damage to your vehicle when an identified uninsured driver is at fault, and is a separate claim from the bodily-injury UM/UIM process above. In California it is capped by statute at the lesser of your vehicle's actual cash value or $3,500, with no deductible under the statute; when you also carry collision coverage, the insurer is required to pay your collision deductible instead of applying it. File the property damage portion alongside, but track it as a separate line item from your bodily-injury UM/UIM claim.
Step 6
Watch the deadlines
California gives you two years from the accident date to file the bodily-injury portion of a UM/UIM claim, and three years for the property-damage portion. These clocks run while you are still treating or negotiating; they do not pause. If your claim is complex or your carrier is slow to respond, do not wait until close to the deadline to get help.
Step 7
If your carrier disputes the value: arbitration
California UM/UIM policies include a mandatory arbitration clause for disputes between you and your own carrier about the value of your claim. If your carrier's offer and your own valuation are far apart, you do not go to court for that dispute, but you also cannot opt out of arbitration. An attorney experienced in UM/UIM arbitration can be useful at this stage specifically, since the process has its own procedural rules separate from a standard lawsuit.
When to get help
When does a UM/UIM claim need a personal-injury attorney?
Many straightforward UM claims, clear liability, moderate injury, cooperative carrier, resolve directly between you and your own insurer without needing outside help. Consider bringing in a personal-injury attorney when any of the following apply:
- Your injuries are serious enough that medical bills and lost wages are likely to approach or exceed your UM/UIM limit, since limit disputes are exactly what arbitration exists for.
- The claim is a UIM case where the at-fault driver's carrier is disputing fault or valuation on the underlying third-party claim, since that dispute has to resolve before your UIM carrier will pay the gap.
- It is a hit-and-run and your carrier is questioning the physical-contact requirement or the corroborating evidence.
- Your own carrier's settlement offer is far below what your medical bills, lost wages, and ongoing treatment plan actually support.
- You are approaching the two-year bodily-injury deadline without resolution.
If none of those apply, most Westminster clients we work with are able to move a UM claim through their own carrier directly, using the sequence above.
Common questions
UM/UIM claim questions we hear from Westminster clients
How long does a UM/UIM claim take to pay out?
It depends on injury severity and whether the case is UM or UIM. A straightforward UM claim with clear liability and completed medical treatment can resolve in a few months. A UIM claim generally cannot finalize until the underlying third-party liability claim against the at-fault driver settles first, which can take longer.
Do I need a police report to file a UM claim?
You should get one whenever possible. It is the primary document your carrier uses to verify what happened and the other driver's insurance status, and it is required practically for a hit-and-run claim to be taken seriously.
Will my premium go up if I file a UM claim?
A UM/UIM claim is paying for damage caused by another driver, not by you, so it is generally treated differently than an at-fault claim on your record. Ask your specific carrier how they handle UM claims for rating purposes, since practices vary.
Can I still sue the uninsured driver directly instead of using UM?
Yes, but an uninsured driver frequently has limited personal assets to collect from, which is the practical reason UM/UIM exists. Many claimants pursue both: the UM claim through their own carrier for prompt payment, while the carrier separately pursues subrogation against the at-fault driver afterward. That subrogation fight is the carrier's, not yours.
What if the at-fault driver has some insurance but denies fault?
If the at-fault driver's carrier disputes fault or offers less than your damages, that is a liability or valuation fight on the underlying claim, and once that resolves or the policy is exhausted, your UIM claim picks up the shortfall. This is one of the more common reasons a UIM case takes longer than a straightforward UM case.
Ready to start a claim
What to have ready when you call
- Your policy number and the date of the accident
- The police report number, once available
- Contact information for any witnesses
- Photos of the damage and the scene
- Medical bills and any documentation of missed work