Published September 3, 2026

Selling a Home With an ADU in Portland or Vancouver

Written by Jeannette Johnson

Tilt-shift photograph of an architectural scale model showing a two-story Craftsman house with a smaller detached cottage behind it, connected by a stone path, with model Douglas firs on a mossy green lawn

What do you need to know before selling a home with an ADU in Portland or Vancouver?

An accessory dwelling unit changes three things about your sale: what your buyer can legally do with it, how their lender can count the rent, and what you have to disclose. In Portland, if you took the System Development Charge waiver when the ADU was built, a recorded covenant bars short-term rentals anywhere on the property for 10 years — and it binds every owner during that period, including your buyer. On the Washington side, a rented ADU inside Vancouver city limits is not exempt from the city's 2026 rental registration program.

By Rick Sadle | September 2, 2026

ADUs have quietly become one of the most common features I deal with in Portland listings, and one of the most misunderstood at the negotiating table.

Sellers treat the ADU as a bonus you add to the list price. Buyers treat it as an income stream. Lenders and appraisers treat it as a documentation problem. And in Portland, the city may have treated it as a trade — a permanent restriction in exchange for a fee break. That last one is where deals fall apart, usually about ten days into escrow.

The Portland covenant that can follow your buyer for 10 years

Portland waives System Development Charges on new ADUs built for long-term residential use. It's a real incentive and a lot of owners took it.

What many of them don't remember is what they signed. Per the city, an approved waiver results in a binding 10-year agreement between the City of Portland and all the property owners who own the property during the covenant's life span. The covenant is tied to the property, not to the person who signed it.

Here's what it actually restricts, straight from the city's program page:

The covenant applies to the entire property. During the 10 years, no structure on the property can be a short-term rental — including single bedrooms in the main house.
Listing any structure on the property on a short-term rental platform is a violation.
The 10-year clock starts on the day of final inspection approval, not the day the permit was pulled and not the day you bought the place.
Getting out of it early requires paying 150% of current SDC fees — the same rate charged for violating it.

Now put yourself in the buyer's chair. They toured a house with a detached ADU, ran Airbnb comps in their head on the drive home, and wrote a strong offer. Nobody mentions the covenant until their lender finds it. That buyer either renegotiates hard or walks.

You can check this yourself in about five minutes. Permit records on PortlandMaps show whether the program applies. Find the ADU's permit, open it, and look at the list of reviewers — if the Revenue Division reviewed it, you'll see "Covenant Recorded."

Do that before you set a price. A covenant isn't a problem, it's a disclosure. Presented honestly to a buyer who wants a long-term tenant or a family member in the back unit, it costs you very little. Discovered late by a buyer who planned to rent it nightly, it costs you the deal.

How lenders and appraisers actually treat the ADU

The second surprise is financial, and it's the reason two buyers can look at the same ADU and arrive at very different numbers.

Under Fannie Mae's Selling Guide, rental income from an existing ADU can only be used to qualify when all of these are true: it's a one-unit principal residence, the income comes from only one ADU even if the lot has two, the transaction is a purchase or a limited cash-out refinance, and the qualifying rental income is capped at 30% of the borrower's total qualifying income.

That 30% ceiling is the one that bites. A buyer qualifying on $9,000 a month of income can count at most $2,700 of ADU rent toward qualifying, no matter what the unit actually rents for. An ADU does not turn a $600,000 buyer into a $900,000 buyer.

Documentation matters too. When the ADU rent is used for qualifying, the appraiser has to provide a Single-Family Comparable Rent Schedule (Form 1007) alongside the appraisal, specifically explaining that the estimated market rent is for an ADU on a one-unit principal residence. If the appraiser can't find ADU rental comps, they're permitted to use similar non-ADU rentals and adjust.

Two practical consequences for you as the seller:

An investor buyer can't use these rules at all — they apply to principal residences. Your ADU is worth something different to an owner-occupant than to someone buying it as a rental.
Appraisal risk is real. A one-unit property with an ADU is still classified as a one-unit property, so the appraiser is looking for one-unit comps with accessory units, and in some Portland and Vancouver submarkets there just aren't many recent ones. That's the same dynamic behind what happens when an appraisal comes in low — worth understanding before you price aggressively on the strength of the second unit.

I'm not going to tell you an ADU adds a specific dollar amount, because it depends on whether it's permitted, whether it's detached, its condition, and what has recently sold nearby with a comparable unit. Anyone quoting you a flat percentage is guessing.

Vancouver: a rented ADU is not exempt from the 2026 registration

Across the river, the compliance question is different. Vancouver's rental registration program took effect January 1, 2026, at $30 per unit per year. The exemption list in the municipal code covers owner-occupied single-family residences without an accessory dwelling unit, and the city's FAQ is explicit that rented ADUs are not exempt, though the unit the owner lives in is.

So if you live in the main house inside Vancouver city limits and rent the ADU, that ADU is a registered rental unit. If the registration was never filed, handle it before a buyer's agent asks.

One caution specific to right now: Vancouver replaced its entire Title 20 Land Use and Development Code effective July 31, 2026, and the online municipal code platform hasn't caught up — the city is directing people to a PDF of the updated code in the meantime. If you're relying on ADU development standards you looked up online, verify them against the current version. I wrote more about the broader shift in Vancouver's 2026 zoning changes.

What to gather before you list

Work through this early. Every item is something a buyer, lender, or appraiser will eventually ask for.

The permit record. Final inspection sign-off is the document that proves the ADU is legal. In Portland, pull it from PortlandMaps and check the reviewer list for a recorded covenant while you're there.
Confirmation of whether the ADU is permitted at all. An unpermitted conversion is not automatically a dealbreaker, but it is a disclosure item and it changes how it can be marketed, appraised, and financed. Do not describe an unpermitted space as an ADU or as a legal second unit.
Your disclosure form. Oregon's OREF 007 and Washington's Form 17 both reach additions, conversions, and known permit issues. This is the same discipline covered in what sellers must disclose in Oregon versus Washington.
The lease, if someone lives there. A tenant in the ADU brings its own notice and showing rules — see selling a house with tenants in Oregon versus Washington before you set a listing date.
Rent history and utility separation details. Separate meters, a separate entrance, and clean rent records make the appraiser's job easier and the lender's faster.
The registration status if the property is a rental inside Vancouver city limits.

Still deciding whether to sell at all rather than keep the income? That's a different calculation — I walked through it in sell your house or rent it out.

One caveat: I'm a real estate broker, not an attorney or a CPA. Covenant terms, permit history, and the tax treatment of rental income are worth reviewing with the right professional for your property.

Frequently Asked Questions

Does a Portland ADU SDC waiver covenant transfer to the buyer?

Yes. The city states the agreement binds all property owners who own the property during the covenant's 10-year life, and that covenants are tied to the property rather than the person who signed. Your buyer inherits the remaining term.

Can my buyer use the ADU rent to qualify for their loan?

Sometimes. Under Fannie Mae guidelines the property has to be a one-unit principal residence, only one ADU's income counts, and the qualifying rental income is capped at 30% of the borrower's total qualifying income. It also has to be a purchase or limited cash-out refinance, and the appraiser must supply Form 1007.

How big can a Portland ADU be?

The maximum is 75% of the primary structure's living area or 800 square feet, whichever is smaller — so a 1,000 square foot house supports a 750 square foot ADU, while anything 1,067 square feet or larger hits the 800 square foot ceiling. The limit doesn't apply to an ADU in the basement of a primary structure at least five years old. No additional off-street parking is required.

Do I have to register my Vancouver ADU as a rental?

If it's rented and inside Vancouver city limits, yes. The exemption covers owner-occupied single-family residences without an ADU; the city's FAQ confirms rented ADUs are not exempt, while the unit the owner occupies is.

Should I get the ADU permitted before selling if it isn't?

It depends on cost, timeline, and what the work would require to bring up to code — sometimes it's worth it and sometimes you're better off pricing and disclosing accurately. What you cannot do is market an unpermitted space as a legal dwelling unit.

An ADU is an asset, but it's an asset with paperwork attached. The sellers who do well are the ones who pull the permit record and the covenant status before pricing, not the ones who find out during the buyer's due diligence.

If you own a home with an ADU anywhere in the Portland–Vancouver metro and you're thinking about selling, I'm happy to pull the permit and covenant history with you and talk through what the second unit is realistically worth to the buyers actually in the market right now. Reach out anytime.

About Rick Sadle

Rick Sadle is the Principal Broker and CEO of The Sadle Home Selling Team at Keller Williams Realty Professionals, serving the Portland, Oregon and Vancouver, Washington real estate markets. With more than 20 years of real estate experience, over 3,500 homes sold and more than $1 billion in team sales volume, Rick is one of the Portland area's most experienced real estate professionals. He is also a weekly real estate expert on KXL 101 FM, where he discusses the Portland and Vancouver housing markets, mortgage rates, housing trends and the economy. Rick is an Oregon-licensed Principal Broker and Washington-licensed Broker.