Adu unit — 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
An ADU is a secondary dwelling on the same lot as a primary residence. People build these to add versatility to their property, whether they need a home office, a gym, or housing for family. Prices are typically influenced by the size of the unit, the complexity of the site, and the interior finishes you select. We can help you determine what fits your budget. Exact pricing confirmed free on the call.
Frequently asked in Hillsboro
What is the cost of an accessory dwelling unit in Hillsboro?
What are the requirements for an affordable ADU in Hillsboro?
What is a prefab ADU, and how does it apply to Hillsboro?
What are the considerations for a detached accessory dwelling unit in Hillsboro?
What is an accessory dwelling unit in Hillsboro?
An accessory dwelling unit (ADU) in Hillsboro, Oregon, is a secondary housing unit on a single-family residential lot, subordinate to the primary dwelling. These units can be attached or detached and are subject to Hillsboro's zoning and building codes. ADUs provide additional housing options and can be used for rental income or family members. We can help you understand the specific regulations and possibilities for ADUs in Hillsboro.
What is the accessory dwelling unit cost in Hillsboro?
What is the ADU cost 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: Meridian Park, The Preserve, South Hillsboro, Brookwood, Orenco — and every surrounding area.
Areas we serve
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