Short answer: Do not assume your existing homeowners policy automatically covers a new or converted accessory dwelling unit (ADU) in every situation. Before construction—and again before renting the unit—tell your insurer or licensed insurance producer exactly what you are changing and how the ADU will be used. Coverage, underwriting and endorsements vary by insurer and policy.
Maryland supports ADU development statewide, but the state’s ADU law is a land-use framework, not an insurance mandate. Your local approval to build an ADU does not determine what your homeowners policy covers.
Why an ADU can change your insurance needs
An ADU may add finished living area, a detached structure, new plumbing and electrical systems, additional occupants, or rental activity. Those changes can affect the amount and type of property and liability protection you need.
The Maryland Insurance Administration explains that homeowners insurance can protect the dwelling, personal property and liability exposures, while policy endorsements can add, remove or modify coverage. That makes the policy itself—not a generic ADU rule—the controlling document.
1. Tell your insurer before construction starts
Contact your insurer or producer before work begins. Explain whether the project is an interior conversion, attached addition, garage conversion or detached ADU; the expected project value; and whether a contractor will perform the work.
This is also a good time to ask whether your dwelling or other-structures limits will remain adequate after the improvement. Maryland’s Insurance Administration specifically recommends shopping for insurance well before making a major addition to a house.
2. Detached ADUs need special attention
Maryland’s consumer homeowners guide describes detached buildings such as garages and sheds under “other structures” coverage. A detached ADU is more complex than an ordinary shed because it is a dwelling space and may be occupied or rented. Ask the insurer how the completed ADU will be classified and whether existing limits are sufficient.
3. Renting the ADU can change the risk
If someone will rent the ADU, disclose that intended use. Maryland’s Office of the Attorney General notes that dwelling insurance is used for properties not occupied by the owner and for rental properties, while homeowners insurance is designed around owner-occupied homes. The correct arrangement for a property where the owner occupies the main home and rents an ADU depends on the insurer and policy.
Do not assume that permission to rent an ADU under zoning rules means your current insurance automatically covers the rental exposure. See our Maryland ADU rental and short-term-rental guide for the separate zoning and rental-law questions.
4. Airbnb and other short-term rentals deserve a separate conversation
Short-term or home-sharing use can create different insurance issues from a conventional long-term tenant. If you plan to use Airbnb, Vrbo or another platform, tell your insurer specifically that the ADU will be used for short-term stays. Do not rely only on coverage offered by a booking platform without understanding exclusions, limits and how it interacts with your own policy.
5. Revisit liability coverage
A separate household, visitors, exterior stairs, walkways, parking areas or shared yards can increase the number of people using the property. Maryland consumer guidance explains that homeowners policies can provide liability protection when someone is injured or their property is damaged because of something the insured owns or does.
Ask whether your liability limit is appropriate after the ADU is occupied and whether an umbrella policy is worth considering for your circumstances.
6. Make sure rebuilding limits reflect the completed project
The cost of adding an ADU does not automatically equal the amount by which an insurer should increase a coverage limit. But a major improvement is a good reason to review replacement-cost assumptions and the declarations page. Ask what documentation the insurer wants when construction is complete.
7. Ask about ordinance or law coverage
Building codes change over time. If a covered loss requires substantial rebuilding, complying with current codes can add cost beyond simply replacing damaged materials. Maryland’s Insurance Administration identifies ordinance or law coverage as an additional home-coverage topic worth reviewing.
Questions to ask your insurance company
- Will my existing policy cover the ADU during construction?
- How will the completed ADU be classified?
- Does a detached ADU fall within my current other-structures limit, or is different coverage needed?
- Should my dwelling or replacement-cost limit increase?
- What changes if a family member occupies the ADU?
- What changes if I rent it to a long-term tenant?
- What changes if I use it for short-term rentals?
- Do I need an endorsement or a different policy form?
- Are my liability limits adequate for an additional household?
- Should I consider umbrella or ordinance-and-law coverage?
- What documents should I provide when construction is finished?
What Maryland homeowners should not assume
There is no single “Maryland ADU insurance policy” required by HB 1466. Insurance depends on the physical project, occupancy, rental activity, insurer underwriting and the language of your policy. Likewise, a building permit or zoning approval does not itself confirm insurance coverage.
If one insurer will not write the risk, that does not necessarily mean every Maryland insurer will refuse it. The Maryland Insurance Administration advises consumers who are turned down to shop other insurers because underwriting requirements differ. Maryland also maintains a property-insurance availability program for eligible applicants who cannot obtain essential coverage in the competitive market.
Where insurance fits in your ADU plan
Insurance should be checked before you sign a construction contract, not after the ADU is occupied. First confirm the property’s ADU rules with our Maryland ADU Jurisdiction Finder. Then use the Maryland ADU Rules Tracker for your local requirements and review insurance alongside permits, utilities and financing.
Primary Maryland sources
- Maryland Insurance Administration — Homeowners Insurance and Consumer Guide
- Maryland Insurance Administration — Endorsements and Riders
- Maryland Insurance Administration — Understanding Homeowners Insurance Rates
- Maryland Attorney General, People’s Insurance Counsel Division — Residential Property Insurance
- Maryland Department of Planning — Accessory Dwelling Units / HB 1466 implementation resources
This article is educational information for Maryland homeowners and is not insurance, legal or financial advice. Coverage varies by insurer and policy. Confirm your situation with a licensed insurance producer or insurer.
What to do next
Start by finding the office that reviews your property. A mailing city or a county guide does not establish your parcel’s authority.
- Find Who Reviews My Property.
- Obtain your parcel identifier, survey, floor plans and utility records.
- Ask the reviewing office which current rules, supporting documents and approvals apply.
- Continue to your planning workspace.
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