Two ADUs in Bend Oregon: The New Rules and What They Mean for Cash Flow

Investor Insights · Bend, Oregon · July 2026

Bend doubled what you can build in your backyard. Here is what the code says, what the City charges, and where the second unit does and does not pay for itself.

For years the ceiling on a Bend backyard was one unit: a single accessory dwelling unit capped at 800 square feet, end of conversation. Then the City Council changed the arithmetic.

Two ADUs in Bend Oregon are now allowed on one lot. That is a real expansion of what a residential lot can produce, and also the part that matters least, because the code was never the binding constraint. Construction cost is.

What Actually Changed

The change came through Ordinance NS-2541, passed on second reading in June 2025 and codified into the Bend Development Code that December. The same package created the rowhouse and legalized a second kitchen in a primary dwelling.

The council did not simply double the allowance. It split it. Councilors debated two 800 square foot units and voted that down four to three, holding the second unit at 500 square feet to push production toward cheaper studio and one-bedroom housing, as OPB reported from the hearing. Bend did not give you a second full unit. It gave you a second small one, and small square footage is the most expensive you will ever build.

The Rules That Govern Two ADUs

Everything below comes from BDC 3.6.200(B). Read it before you pay a designer.

The floor area exclusion is worth a second read. A 500 square foot unit with a carport entered only from outside keeps its full 500 square feet of living space and gains usable structure.

The Lots That Are Quietly Disqualified

Before pricing anything, confirm the lot is eligible. Several categories are shut out and none are visible from the street. ADUs are prohibited on any lot created through a middle housing land division, so a duplex or quadplex site split under the state expedited process cannot host one, and they are prohibited in cottage developments. Small dwelling unit developments allow one ADU capped at 600 square feet. Rowhouse lots allow one.

The Sewer Test Nobody Budgets For

This goes unmentioned in almost every other article about two ADUs in Bend Oregon, and it is the most common way a second unit dies late. Under BDC 3.6.200(B)(4), if the second ADU pushes the lot above its zone's maximum density, that unit is not permitted when the sanitary sewer main fails any of three capacity conditions:

This is not a fee you can pay to make go away. It is a capacity finding about pipe in the street, and it applies only to the second unit.

So sequence accordingly: run a sewer capacity check with the City before commissioning a drawing. Bend's fee for a basic certificate is trivial against designing a unit that cannot be permitted. It bites hardest in older neighborhoods on aging mains, exactly where deep lots fit a second unit.

The Fee Cliff at 800 Square Feet

Most published guidance on Bend ADU costs is wrong here. You will find claims that system development charges run $8,000 to $20,000. The City's adopted schedule says otherwise.

On the City of Bend SDC schedule, the Accessory Dwelling Unit category shows no water charge and no sewer charge, just a $1,062 transportation SDC. Add the $5,211 Bend Park and Recreation District SDC, collected by the City on the District's behalf, and a compliant ADU carries about $6,273.

Go one square foot past 800 and the unit stops being an ADU. It is reclassified into the single-unit and middle housing category, tiered by size, paying full water, sewer, and transportation SDCs.

A 900 square foot unit pays $16,463 in City SDCs plus $9,699 in park SDCs: $26,162 against $6,273, a swing of $19,889 for 100 extra square feet. KTVZ reported in 2024 on a Bend homeowner who halted his project after the City assessed roughly $33,000, because at 900 square feet it was no longer an ADU. Two compliant ADUs, at about $12,546 combined, cost far less in fees than one oversized unit.

Two offsets help. The City publishes five free pre-approved plans, and the Bend Chamber's Design Library adds permit-ready plans under a master re-issue permit, against $5,000 to $10,000 for custom design. Bend's SDC deferral moves the charge off your construction draw.

What ADU-Scale Units Actually Rent For

This is where optimism outruns the data. A 500 square foot unit does not rent for two thirds of an 800 square foot unit. It rents for less, because rent tracks bedrooms and function, not area.

Bend studios ran roughly $1,395 to $1,640 per month in mid-2026 depending on the source, with one-bedrooms between $1,600 and $1,840. Detached ADUs price at the softer end: no garage, shared driveway and yard, a landlord across the fence. Our citywide read is our 2026 analysis of average rent in Bend Oregon; our unit-level method is how much rent to charge for a Bend rental.

The right panel is the case for the second unit. At a modeled $1,350 per month, a 500 square foot ADU earns about $2.70 per square foot, against $2.00 for the 800 and $1.93 for a single-family home at the $2,700 collected rent in our Q2 report. Small units are efficient revenue generators and even less efficient to build.

Four Ways to Add the Second Unit

Cost is where this decision gets made, and "what does an ADU cost in Bend" is the wrong question. What it costs built this way is the right one.

Central Oregon guidance puts a new detached 600 to 800 square foot ADU near $200,000 to $300,000, and converting existing space near Bend at $100,000 to $180,000. Comparable Oregon markets run $130 to $260 per square foot detached, with modular 10 to 25 percent below stick-built.

Note the perverse arithmetic: the 500 square foot unit costs more per square foot than the 800, because a kitchen, a bathroom, and a permit do not shrink with the floor plan.

The Year-One Math

Below is a modeled Year-One pro forma for an owner who already holds the land, the only scenario where this works. Both units are priced as detached new construction at the midpoints above. Every figure is modeled, not quoted.

The second unit lifts the blended yield from 4.6 to 5.0 percent, because it inherits paid-for infrastructure: site work, utility trenching, driveway, mobilization. Isolated, it costs $195,273 more and adds $10,778 of net operating income, a 5.5 percent marginal yield.

The Honest Conclusion: How You Build Decides

Five and a half percent does not clear the cost of the money. Construction loans and equity lines in this cycle have sat near 7 percent, so borrowing at 7 to earn 5.5 is negative leverage.

But that 5.5 percent belongs to one build path. The unit produces the same $10,778 of income however it gets built, so the cheaper the path, the higher the return on identical rent.

Only the interior conversion clears the cost of debt with real margin. An attached addition lands near break-even. Detached and above-garage builds do not get there. So the conclusion is narrower than "build a second ADU": if you have convertible space, the second unit is one of the better returns available on a Bend residential lot. If you are pouring a new foundation for 500 square feet, you are buying appreciation, flexibility, and future family or workforce housing, not cash flow.

Both are legitimate reasons. Just know which purchase you are making. Our take on the underlying asset is is real estate in Bend a good investment, and the single-unit version is our earlier piece on ADUs in Bend Oregon.

The Rent Cap Exemption Most Owners Miss

Oregon caps annual rent increases on existing tenancies at 9.5 percent for 2026 per the Oregon Department of Administrative Services. But under ORS 90.323, that cap does not apply when the first certificate of occupancy for the unit was issued less than 15 years before the increase notice.

A newly built ADU starts its own 15-year clock, sitting outside the percentage cap while the 1978 house in front of it does not. The other rules still apply: no increase in the first year of tenancy, one increase per 12-month period, 90 days written notice. The mechanics are in our guide to how much you can raise rent in Oregon in 2026. That exemption is worth real money over a hold and partly offsets the thin going-in yield, and owners forfeit it by never documenting the occupancy date.

Taxes and Operating Cost Creep

Three costs get left out of nearly every backyard ADU spreadsheet we review. First, property tax. Under Measure 50, new construction is added to the roll as an exception to the three percent growth limit, with the added value converted through the county changed property ratio. The Deschutes County Assessor publishes a tax estimator, and Bend offers no ADU tax exemption.

Second, per-unit municipal charges. Bend's transportation fee is assessed per dwelling unit, and separately metered water and sewer each add base charges. Small individually, but across two units over a 20-year hold they turn a 5 percent pro forma into a 4 percent reality.

Third, with three tenancies on one parcel, proximity turns one bad fit into everyone's problem, which is why our approach to screening tenants tightens on multi-unit lots.

The Two-ADU Playbook

Two ADUs in Bend Oregon is a useful tool, not a shortcut. Earlier in the process, start with our first-time landlord checklist, our breakdown of property management costs in Bend, and the latest Bend rental market report.