How Do You Insure an Accessory Dwelling Unit on Your Property?
A garage converted into a small apartment or a freestanding cottage in the backyard can quietly turn a simple homeowners policy into a more complicated one.
The short answer
An accessory dwelling unit, often called an ADU, may already be covered to some degree under a standard homeowners policy’s other structures coverage, which typically applies to detached buildings on the property. But that coverage is usually limited to a percentage of the main dwelling’s insured value and often assumes the structure isn’t a separate rented residence. Once an ADU is occupied by a tenant rather than family, or once its value exceeds what other structures coverage provides, it typically needs its own dwelling coverage or a landlord-style policy instead.
Where other structures coverage stops being enough
Other structures coverage exists for things like a detached garage, shed, or fence — structures that support the main home rather than functioning as an independent residence. An ADU built out as a full living space, with its own kitchen, bathroom, and separate entrance, often exceeds both the intent and the dollar limits of that coverage category. Because other structures coverage is usually calculated as a fraction of the main home’s insured value, a well-built ADU can easily be worth more than that limit allows, leaving a meaningful gap if it’s ever damaged or destroyed.
Why occupancy changes the coverage needed
The biggest shift happens when an ADU is rented out rather than used by family or kept as a guest space. A standard homeowners policy is generally built around owner-occupied use, and renting out a portion of the property — even a small one — can affect how a claim is handled, and in some cases whether coverage applies at all if the insurer wasn’t informed of the rental arrangement. This is similar to the shift that happens with a full rental property, just at a smaller scale, and it typically calls for either an endorsement disclosing the rental use or a separate landlord-style policy covering the ADU specifically.
What the tenant’s side typically needs
Just as with any rental, the ADU’s insurance covers the structure and the owner’s liability, not the tenant’s personal belongings. A tenant living in an ADU generally needs their own renters insurance to protect their possessions and add their own liability coverage, separate from whatever the property owner carries on the structure itself. This division of responsibility is easy to overlook when the arrangement feels informal, such as renting to a relative or a friend, but the insurance mechanics work the same regardless of how personal the arrangement feels.
Loss of use and rental income considerations
If an ADU becomes uninhabitable after a covered loss, two different financial questions come up depending on who’s affected. For an owner living in the main home, coverage for loss of use typically addresses temporary housing costs, a topic covered in more detail in a broader explanation of loss of use coverage. For an owner renting out the ADU, the more relevant concern is lost rental income while repairs are underway, which isn’t automatically covered under a standard homeowners policy and often requires a specific endorsement or a landlord policy that includes rental income protection.
What to weigh
Insuring an ADU properly starts with an honest accounting of how it’s actually used — as extra space for family, an occasional guest suite, or a genuine rental generating income — since each scenario points toward a different coverage structure. Disclosing the ADU and its use to an insurer directly, rather than assuming it’s automatically folded into the existing policy, is what prevents an unpleasant surprise if a claim ever needs to be filed.