Accessory dwelling unit services — Hillsboro, OR
Last updated: September 24, 2026
What affects the price
Building an ADU is a custom project, so costs vary based on your specific choices. Site conditions are the biggest factor; if your land requires significant grading, utility extensions, or foundation work, those expenses add up quickly. Choosing high-end finishes, custom cabinetry, or complex roof lines will also push the budget higher compared to a standard design. Prefabricated units often offer predictable costs, while custom site-built structures allow for more flexibility but can be harder to estimate upfront. Exact pricing confirmed free on the call.
About this service
These services cover the entire lifecycle of building a backyard home, from initial property assessments and architectural design to navigating local zoning permits. You need this when you want to add living space to your property but don’t know where to start with city regulations or site feasibility. Professionals handle the paperwork, site planning, and technical requirements so you can focus on the final layout and how you plan to use the additional square footage on your lot.
Frequently asked in Hillsboro
What are the requirements for an accessory dwelling unit contractor in Hillsboro?
What is the best ADU for a property in Hillsboro?
What is involved in accessory dwelling unit construction in Hillsboro?
What are the permit requirements for an ADU in Hillsboro?
Are modular accessory dwelling units a good option in Hillsboro?
How do I find an accessory dwelling unit contractor in Hillsboro?
What is the cost of an accessory dwelling unit in San Diego compared to Hillsboro?
Also serving nearby: Beaverton · Portland · Vancouver · Gresham · Salem
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of Hillsboro — population 107,730; about 4,168 residents per square mile across 25.8 sq mi. ZIP codes covered include 97123, 97124, 97129.
Neighborhoods served in Hillsboro: Evergreen, South Hillsboro, North Hillsboro, Brookwood, Downtown Hillsboro — and every surrounding area.
Areas we serve
Browse by state, then city.