ADU Cost & Pre-Approved Plans in Bend, Oregon

If you're a homeowner in Bend, Oregon weighing an accessory dwelling unit, the first question is almost always the same: how much will it cost? The honest answer is that most ADUs in Bend land between $200,000 and $400,000 — but where your project falls in that range depends heavily on the type of ADU, your lot, and the finish level you choose. Below we break down real 2026 ranges from our own builds across Bend and Deschutes County, explain how the City of Bend's free pre-approved ADU plans can trim both your design costs and your permitting timeline, and point you to a free calculator so you can estimate your own project in about a minute.

ADU cost in Bend by type

There are three common ADU paths in Bend, and the type you choose is the single biggest driver of cost. Here's how they compare:

Garage conversion ADUs — the cost-effective path

Converting an existing attached or detached garage into a code-compliant living unit is typically the most affordable way to add an ADU in Bend, usually $200,000 to $300,000. Because the foundation, walls, and roof already exist, you're mainly paying for interior framing, insulation, a kitchen and bath, utility connections, and finishes rather than an entire new structure. Garage conversions also tend to move faster through both construction and permitting.

Detached ADUs — the most flexible

A fully detached ADU is a stand-alone structure on your lot, typically 400 to 900 square feet with its own kitchen, bath, and entrance. It's our most-requested ADU type in Bend because it offers full privacy and the strongest rental-income potential. Expect $250,000 to $400,000 or more, with high-end finishes and difficult sites pushing toward the top of that range.

Attached ADUs

An attached ADU is a new addition built onto your primary home with a separate entrance. It's common for multi-generational living and for lots where a detached structure isn't feasible due to setbacks. Costs generally fall between the other two types.

What drives ADU cost in Bend

Two ADUs of the same square footage can differ by tens of thousands of dollars. The biggest cost factors we see on Bend projects:

• Site conditions. Slope, soil, tree clearing, and access for equipment all affect cost — Bend's east-side infill lots, established west-side neighborhoods, and acreage in Tumalo each present different challenges.
• Utility connections. Running water, sewer, and electrical to a detached unit costs more than tapping into systems that already serve a garage.
• Finish level. Standard vs. premium cabinetry, countertops, flooring, and fixtures can swing the budget significantly.
• Permits & SDCs. Budget for City of Bend or Deschutes County permit fees, plan review, and any applicable system development charges for water and sewer.
• Size and layout. More square footage and complex rooflines cost more per project, though cost per square foot often improves slightly as size increases.

Don't forget permitting and timeline

Every ADU in Bend requires permits — through the City of Bend within city limits, or Deschutes County for rural properties. Permitting typically takes 6 to 12 weeks, and once approved, most ADU builds run 4 to 7 months (garage conversions often finish faster, around 3 to 5 months). At Rockin' K we manage the entire permitting process, including engineer coordination and inspections, so the timeline and the paperwork don't fall on you. You can read more on our ADU construction page.

One recent change worth knowing: the City of Bend now allows up to two ADUs on a single-family lot, which opens the door to a second rental or family unit on the same property. Our guide to Bend's two-ADU rule covers the new size limits and what it means for your lot.

Pre-approved ADU plans in Bend — a faster, cheaper path

One of the best ways to bring down both the cost and the timeline of an ADU in Bend is to start from a pre-approved plan. Since 2023, the City of Bend's pre-approved ADU plans program has offered homeowners a library of plan sets that have already passed building plan review and meet code. The city has continued to expand the program, recently adding several new plan sets — including accessible studios, two-bedroom units, and studios with a garage — available at no cost for site-specific permitting within Bend.

Why it saves money: a pre-approved plan removes the cost of designing an ADU from scratch, and because city staff spend less time reviewing a plan they've already vetted, the review process is faster and more predictable. Where a custom design can add weeks of drafting plus a longer review, pre-approved plans typically move through review in roughly 4 to 8 weeks.

A few things to know before you choose this route:

• The city plan sets themselves are free, but you'll still pay building permit and plan review fees, planning fees, and system development charges (SDCs) for water and sewer.
• You generally can't modify a pre-approved plan on your own — you'll work with a designer or licensed general contractor to adapt it to your lot, and you'll need a site plan at minimum.
• Not every plan fits every lot. Setbacks, slope, utilities, and access still determine which plans are feasible on your property.

Want to browse what's available? Start with the City of Bend ADU Resource Hub and the Bend Chamber's Pre-Approved ADU Design Library, and read the Central Oregon Daily coverage of the program for background. Rockin' K builds from pre-approved plans regularly — we'll help you pick a plan that fits your lot and handle the permitting and site work from there. (Oregon is also developing a statewide "Oregon Homes" permit-ready plan program under HB 2258, currently in rulemaking — we'll update this guide as it rolls out.)

Does an ADU pay off in Bend?

For most homeowners, yes. Bend's housing market values ADUs for their rental income potential and multi-generational flexibility. Long-term rentals are allowed throughout Bend, and many of our clients use ADU rental income to offset their mortgage within the first year of completion. A well-built ADU also returns a strong portion of its construction cost in added home value at resale.

Estimate your ADU cost in minutes

Ranges are useful for deciding whether a project is worth exploring, but the next step is seeing a number tailored to your project. Our free cost calculator uses real Rockin' K project data — pick your ADU type, size, and finish level and you'll get a ballpark in about a minute. When you're ready for a firm number, we'll visit your site and put together a detailed written proposal.