The short answer: it depends on how your ADU is built and used
Many homeowners assume their existing homeowners insurance policy automatically extends to a newly built ADU. In practice, coverage typically depends on whether the ADU is physically part of your main home or a separate structure, and whether you plan to live in it, house family, or rent it out.
How coverage typically differs by ADU type
| ADU Type | Typical Insurance Treatment |
|---|---|
| Attached or interior conversion (garage, basement) | Often treated as part of the main dwelling and covered under your existing policy, especially when used by family — but confirm with your carrier rather than assuming. |
| Detached ADU (backyard cottage) | Typically falls under the "other structures" portion of a standard policy, which is commonly limited to a set percentage of your main dwelling coverage — often not enough on its own to fully rebuild the ADU. |
| Any ADU used as a long-term rental | Generally requires landlord or rental-property insurance in addition to (or instead of) a standard homeowners policy, to cover tenant-related liability and property damage. |
These are general patterns, not guarantees about your specific policy — insurance carriers vary in how they classify and price ADU coverage. See our ADU Airbnb rules guide if you're considering short-term rental use, since that changes the insurance picture even further.
What to do once your ADU is complete
- Contact your insurance agent before move-in or first tenancy. Most carriers need to formally add the new structure to your policy, whether by increasing your "other structures" coverage limit or issuing a separate policy.
- Ask specifically about rebuild cost, not just add-on cost. A generic percentage-based "other structures" limit may not reflect what it would actually cost to rebuild your specific ADU.
- Clarify who's covered if family lives in the ADU rent-free versus a paying tenant — carriers can treat these differently for liability purposes.
- Ask about the premium impact before you commit to a rental strategy. Adding a rented ADU to your policy commonly increases your annual premium; get a specific quote for your situation rather than relying on general estimates.
This is general information, not insurance advice
Insurance products, terms, and pricing vary significantly by carrier and by property. This page describes common patterns in how ADUs are typically treated, not a quote or guarantee for your specific policy. A licensed insurance agent is the right resource for your actual coverage options and costs.
Frequently asked questions
Not fully, in most cases. Detached ADUs typically fall under a limited "other structures" coverage category that may not be enough to fully rebuild the unit. Contact your insurance agent once construction is complete to confirm and adjust your coverage.
Generally yes — renting an ADU to a long-term tenant typically requires landlord or rental-property insurance to cover tenant-related liability and property damage that a standard homeowners policy doesn't address.
Often it's treated as part of your main dwelling since it's physically attached, but confirm this directly with your insurance carrier rather than assuming — treatment can vary by policy.