Adu permit — 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.
Frequently asked in Hillsboro
What are the requirements for accessory dwelling unit construction in Hillsboro?
How do I find an ADU builder in Hillsboro?
What are the options for homes with mother-in-law suites in Hillsboro?
Homes with mother-in-law suites in Hillsboro are typically designed as accessory dwelling units (ADUs), offering flexible living spaces for family members or rental income. Options range from attached additions to detached backyard cottages, each customizable to fit your needs and property. Our affiliated professionals can help design and build a suite that complements your existing home. They ensure it meets all local building standards. This provides a functional and comfortable space.
What is the cost of an ADU in Hillsboro?
What are the benefits of a modular accessory dwelling unit in Hillsboro?
A modular accessory dwelling unit in Hillsboro can offer faster construction times and potentially lower costs due to factory-controlled production. These units are built off-site and then transported and assembled on your property. Our affiliated professionals can guide you on the suitability of modular ADUs. They ensure proper integration and compliance with local codes. This provides an efficient building option.
What ADU services are available in Hillsboro?
How close can an ADU be to the property line in 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: The Orenco Neighborhood, Downtown Hillsboro, Brookwood, Raleigh Hills (nearby), North Plains (nearby) — and every surrounding area.
Areas we serve
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