Selling a House With Unpermitted Work in Washington

Can you sell a house with unpermitted work in Washington State?

Yes. Unpermitted work does not make your home unsellable in Washington, but it does change three things. You must disclose it on the Form 17 Seller Disclosure Statement based on your actual knowledge, even if a previous owner did the work. The appraiser generally will not count unpermitted space in your home's gross living area. And your buyer's lender may balk at financing a home with work that was never inspected. You have three real paths: permit it after the fact, disclose it and sell as-is, or price it in and let the buyer decide.

By Samantha Schlegel | July 14, 2026

The finished basement was already there when you bought the house. So was the converted garage, or the bedroom someone framed under the stairs, or the deck that appeared sometime in the nineties.

Nobody asked about permits then. But you're listing now, and your agent just handed you Form 17, and there's a question on it that stops you cold: Were all building permits obtained?

You don't know. And that's exactly the problem.

This is one of the most common questions I get from sellers in Shoreline and North Seattle, and it makes complete sense. Our housing stock is old. A lot of these homes were built between 1940 and 1965, and almost all of them have been touched since - basements finished, garages converted, bathrooms added, ADUs carved out of a daylight basement during the last decade. Some of that work was permitted. A lot of it wasn't.

Here's what actually happens when you sell a house with unpermitted work in Washington, and how to decide what to do about it before you list.

What Washington law actually requires you to disclose

Washington's seller disclosure law lives in RCW 64.06.020, and it produces the document you know as Form 17.

The structural section of Form 17 asks, in plain language, whether there have been any conversions, additions, or remodeling - and if so, whether all building permits were obtained and whether all final inspections were obtained.

Three things about that question matter enormously:

It's an actual-knowledge standard. You disclose what you know. You are not required to become a building inspector or hire an investigator. If you honestly don't know whether the previous owner permitted the basement, the correct answer is "don't know," not a guess in either direction.

It applies to work you didn't do. This is where sellers get tripped up. If you know the deck was built without a permit - even if it was built in 1998 by someone whose name you've never learned - you know it. Inherited ignorance is not the same as inherited knowledge.

"Don't know" is an answer, not an escape hatch. Checking that box is honest, but it doesn't make the issue disappear. It hands the question to the buyer, who will very likely go looking. City of Shoreline permit records are searchable online. So are Seattle's. A motivated buyer's agent finds this in about ten minutes.

And here's the piece that should get your attention: failing to disclose unpermitted work you knew about isn't a technicality. It's the kind of thing that supports a fraud or nondisclosure claim after closing — the buyer coming back for the cost of fixing it, or worse. Disclosing it, on the other hand, moves the responsibility to the buyer's side of the table. Disclosure is not the thing that costs you money. Concealment is.

The two hits nobody warns you about: the appraisal and the loan

Most sellers worry about the legal exposure. It's real, but it's manageable. The financial hit is the part that catches people off guard.

The appraiser probably won't count it.

Appraisers working on conventional loans measure homes under the ANSI Z765-2021 standard. Two rules from that standard hit unpermitted space hard:

• Below-grade space isn't gross living area — period. If any part of a level is below the exterior grade, the whole level is below-grade. Your beautifully finished 700-square-foot basement is not adding 700 square feet to your appraised living area, permitted or not. It gets valued separately, and at a discount.

• Converted spaces only count if the permits are in place. A garage or porch conversion counts toward gross living area only when it's properly permitted, finished, heated, and has adequate ceiling height. Miss the permit and the appraiser has grounds to exclude it.

In Shoreline, homes are running around $530 per square foot as of mid-2026. It's tempting to multiply that by your unpermitted square footage and imagine what you're losing. Don't - that math overstates it, because below-grade space was never going to appraise at full above-grade rates anyway. But the direction is right. Unpermitted space contributes less to your value than you think it does, and sometimes it contributes nothing on paper.

The lender may be the one who kills the deal.

Lenders don't like collateral with uninspected work in it. They're underwriting a 30-year loan against a house where the wiring behind the drywall was never looked at by anyone. Depending on the scope, an underwriter can condition the loan, require the work be permitted or removed, or simply decline.

That's the real risk. Not a lawsuit years later - a financing fallout three weeks before closing, in a market where you can't afford to go back on the market with a stale listing.

Your three options, honestly compared

1. Permit it after the fact

You go to the city, pull an after-the-fact permit, bring the work up to current code, and get it inspected.

This is the cleanest outcome and the most expensive one. In Shoreline, permit fees may be doubled as a penalty for work started without a permit, and a separate Investigation Inspection permit is required before you can even submit the building permit. Seattle's SDCI charges a tiered special investigation fee based on project valuation, plus reinspection fees on top.

Then there's the real cost: bringing decades-old work up to current code. That 1990s basement bedroom may need egress windows, updated electrical, and proper ceiling height. Walls come open. Timelines stretch. I've seen this take three months.

Choose this when: the work is high-value (a full ADU, a bedroom that meaningfully changes the bed count), the underlying construction is sound, and you have time before you need to be on the market.

2. Disclose it and sell as-is

You check the box honestly, hand over what you know, price accordingly, and let buyers price the risk themselves.

This is the fastest path and it's completely legitimate. It also narrows your buyer pool - you're steering toward cash buyers, investors, and buyers with flexible financing, and away from the buyer using a conventional loan with a nervous underwriter.

Choose this when: the work is cosmetic or low-stakes, you need speed, or the cost to permit exceeds what you'd recover. If you're already weighing this trade-off, my breakdown of whether to sell your Shoreline home as-is or fix it first walks through the same math.

3. Disclose, price it in, and offer a credit

The middle path, and often the smartest one. You disclose, you price the home with the issue baked in, and you go into negotiation prepared to offer a repair credit rather than a price cut if a buyer pushes.

Choose this when: the work is real but fixable, and you'd rather trade dollars at closing than trade three months of your life at the permit counter.

What the 2026 market has to do with this

Timing matters here more than it did two years ago.

King County active inventory is up roughly 31% year over year, and Shoreline's median sale price sat around $757,500 in May 2026 - down about 2.3% from a year prior. Homes are still moving quickly, but buyers have choices again.

In 2021, a buyer would waive the inspection and take the unpermitted basement without blinking. In 2026, that same buyer has four other houses to look at, and their agent is telling them to scope the sewer, pull the permit history, and negotiate.

What that means for you: the cost of an unaddressed surprise is higher now than it was. A buyer discovering unpermitted work mid-escrow in this market doesn't shrug - they renegotiate, or they walk to the next listing. Getting ahead of it before you go live is worth real money. If you're deciding how much pre-listing work is worth doing at all, I broke down what actually pays off in a 2026 King County renovation and what it truly costs to sell a Shoreline home this year.

The honest answer to "what should I do?" depends on what the work actually is, how much of your value depends on it, and how fast you need to move. That's not a question you can answer from a blog post. It's a question you answer by pulling your property's permit history and looking at the gap between what's on file and what's actually standing there - which is exactly what I do with sellers before we set a price. It also helps to know where King County property trends are heading before you commit to a timeline.

Frequently Asked Questions

Do I have to disclose unpermitted work in Washington if the previous owner did it?

Yes, if you know about it. Form 17 is based on your actual knowledge, not on who performed the work. If you learned during your own purchase, from a neighbor, or from a prior inspection that the basement was finished without permits, that's knowledge you're required to disclose.

Can a buyer sue me for not disclosing unpermitted work?

Yes. Knowingly concealing unpermitted work can support a claim for fraud or nondisclosure, and buyers have pursued sellers for the cost of correcting the work - sometimes years after closing. Disclosing it shifts that responsibility to the buyer. Talk to a real estate attorney if significant money is involved.

Will unpermitted square footage count in my appraisal?

Usually not. Under the ANSI standard used for conventional loan appraisals, below-grade space never counts toward gross living area, and converted spaces like garages only count when they're properly permitted, finished, and heated. Unpermitted space typically gets valued separately, at a discount, or not at all.

How much does an after-the-fact permit cost in Shoreline?

Shoreline may double the standard permit fee as a penalty and requires a separate Investigation Inspection permit before you can submit the building permit. The larger cost is usually the construction itself - bringing older work up to current code, which can mean opening walls, adding egress windows, or redoing electrical.

Can a buyer still get a mortgage on a house with unpermitted work?

Sometimes, but it depends entirely on the scope and the underwriter. Minor unpermitted work often passes without comment. A full unpermitted living unit or major structural addition can get a loan conditioned or declined - which is why financing fallout, not a lawsuit, is the risk I'd worry about most.

Should I just get a pre-listing inspection to find out what's unpermitted?

An inspection tells you about condition, not permits - for permits, you pull the city's records. But be aware: anything you learn becomes something you know, and therefore something you must disclose on Form 17. That's not a reason to avoid finding out. It's a reason to find out early, while you still have time to decide what to do about it.

The bottom line

Unpermitted work is not a dealbreaker in Washington. It's a disclosure obligation, an appraisal question, and a financing risk - three things that are all far easier to manage before you list than after you're under contract.

Pull your permit history. Find out what's actually on file. Then decide, with real numbers in front of you, whether to permit it, price it in, or disclose it and move.

If you're staring at Form 17 right now wondering how to answer that question honestly without torpedoing your sale, that's a conversation worth having before your listing goes live. I'm happy to pull your property's permit records and walk through what it means for your price. Reach out anytime.

This post is general information for Washington home sellers, not legal or tax advice. Permit requirements and penalties vary by jurisdiction, and disclosure questions with real money at stake are worth reviewing with a real estate attorney.

About Samantha Schlegel

Samantha Schlegel is a residential listing specialist serving Shoreline and the greater Seattle area, with a focus on sellers navigating complex situations like probate, inherited homes, divorce, and relocation. She believes every seller deserves a strategy tailored to their real circumstances, not a one size fits all approach. Samantha works with Compass Real Estate and is known for guiding clients through tough transitions with clarity and care.