What devalues a house the most, and why?
Structural and water problems do the most damage to a house's value, because they're expensive, they can hide more damage, and they make a buyer's lender and insurer nervous. A roof at the end of its life, a wet crawlspace or a failed sewer line can each weigh on an offer far more than worn floors.
The problems that cost a house the most value tend to be expensive to fix, hard to size up, since nobody knows how far they go until someone opens a wall or digs a trench, and able to get in the way of a buyer's loan. In the Puget Sound that usually means water. Roofs here take years of rain and moss, crawlspaces collect moisture, and older houses can still have an original side sewer or a heating oil tank in the yard. Unpermitted additions and garage conversions are the other big one, because the buyer inherits the work and whatever the city says about it. None of this makes a house unsellable. What changes is who buys it and how the price gets set. A buyer with a mortgage and a short inspection period may walk away, while a cash buyer prices the repair into the offer and closes with the problem in place.
Which Puget Sound problems cost buyers the most?
In older Puget Sound houses the costly ones are moss-damaged roofs, wet crawlspaces, old heating oil tanks, failing side sewers, septic systems that need a county report before sale, and parcels in a floodplain or on a landslide-prone slope. Each one has a public source that tells you, or a buyer, where you stand.
Age is a big part of it. By the Census Bureau's 2020-2024 survey, 52.8% of Seattle's homes and 64.3% of Tacoma's were built before 1980, so plenty of the houses for sale here still have original pipes and old heating systems.
| Why buyers worry | What it can mean for the sale | Where to check | |
|---|---|---|---|
| Moss and an aging roof | Moss holds water against the roofing and can shorten a roof's life | Some lenders and insurers want a leaking or worn-out roof dealt with before closing | A roofer's inspection; Form 17 asks if the roof has leaked in the last five years |
| Wet crawlspace or basement | Standing water can mean rot, mold or drainage trouble at the foundation | Moisture findings in an inspection often turn into repair requests or credits | Form 17 asks whether the basement has flooded or leaked, and about settling or sliding |
| Heating oil tank | An old tank can leak, and contaminated soil is costly to clean up | A buyer will ask whether it was tested, decommissioned or removed | Form 17 asks about fuel storage tanks; the state's PLIA has a heating oil loan and grant program |
| Side sewer | In Seattle the owner owns the side sewer all the way to the public main | A camera scope that shows roots or breaks usually leads to a repair request | Seattle Public Utilities' side sewer guidance; a plumber's sewer scope |
| Septic system | A failing drainfield is expensive to replace | In Pierce County the health department's Report of System Status is needed before the sale | Tacoma-Pierce County Health Department |
| Floodplain or steep slope | Flood insurance costs or building limits come with the parcel | Form 17 asks about floodplains and critical areas on the property | Skagit County's FEMA floodplain map; Seattle's environmentally critical areas maps |
| Unpermitted work | The buyer inherits the work and any permit problem that comes with it | An appraiser may not give full credit for unpermitted space | City or county permit records; Form 17 asks whether permits and final inspections were obtained |
Source: RCW 64.06.020, the seller disclosure statement (Form 17) questions, checked 2026-09-30
Heating oil tanks
A tank can still be sitting in the yard of an older house long after the heat switched to gas or a heat pump. Washington's seller disclosure form asks about fuel storage tanks, so a tank you know about goes on the form. The state's Pollution Liability Insurance Agency runs a heating oil loan and grant program for tank owners.
Side sewers
Seattle Public Utilities is plain about the side sewer, the pipe that runs from the house to the public sewer: the property owner owns it and maintains it all the way to the main. Roots and old joints are the usual trouble, and a plumber's camera scope shows what's down there before anyone commits.
Septic in Pierce County
In Pierce County, a house on septic needs a Report of System Status from the Tacoma-Pierce County Health Department before it's sold. It rests on an inspection by a certified company with the tank pumped, the department's review takes about ten business days, and the report is good for a year.
Floodplains and steep slopes
In Skagit County, the FEMA 100-year floodplain map along the Skagit River takes in the west side of Mount Vernon and the south side of Sedro-Woolley. In Seattle, the city maps landslide-prone and steep-slope land as environmentally critical areas, and work on those parcels needs a geotechnical review.
What doesn't hurt value as much as you'd think?
Paint colors, dated light fixtures, old carpet, worn cabinets and clutter usually matter less than sellers fear. Buyers expect to change them, they cost little to fix next to a roof or a sewer line, and a cash buyer prices them in as a line item. A deep clean often does more than a remodel.
Where cosmetic problems do cost you is in how a house photographs and shows on a listing. Most buyers see the listing photos before they ever walk in, and a dark, cluttered house gets fewer showings. That's a reason to clean and clear out before you list, and a poor reason to put in a new kitchen.
For a table of what's usually worth fixing before a sale and what usually isn't, see what not to do before you sell your house.
Can you still sell a house with these problems?
Yes. You can sell it as it is for cash, list it as it is and price it for the condition, or fix the worst of it and then list. Which one leaves you more depends on the repair bill, your timeline, and whether a buyer with a mortgage could close on the house at all.
- Sell it as-is for cash
- A buyer paying cash takes the house with its problems and prices them in. There are no repairs to arrange and no showings, and no buyer's loan that can fall apart over an inspection report.
- List it as-is
- Priced for its condition, the house reaches remodelers and buyers who want a project. Their lender and their inspector still get a say before closing.
- Fix the worst, then list
- This makes sense when one or two repairs open the house up to ordinary buyers, and those repairs cost less than the price they add.
How a cash sale on a house that needs work goes, and what the buyer takes on, is on the page about selling a house as-is. To put the three routes next to each other with their costs, see the comparison of a cash offer and a listing.
Two situations add a layer of their own to this. An inherited house often comes with years of put-off repairs and rooms full of belongings, which the guide to selling an inherited house covers. A rental has notice rules for the tenants, set out in the guide to selling a house with tenants. The steps from a first call to closing are laid out on the how-it-works page.
Do you have to disclose them?
Yes, you do when you know about them. Washington's seller disclosure statement, Form 17, asks directly about roof leaks, a flooded or leaking basement, settling or sliding, remodeling and its permits, fuel storage tanks, and floodplains or critical areas. Selling as-is doesn't take you off the hook for the form.
The questions on the form in use in 2026
- Has the roof leaked within the last five years? (question 4.A)
- Has the basement flooded or leaked? (4.B)
- Have there been any conversions, additions, or remodeling, and were all building permits and final inspections obtained? (4.C)
- Has there been any settling, slippage, or sliding of the property or its improvements? (4.E)
- Are there any shorelines, wetlands, floodplains, or critical areas on the property? (7.D)
- Are there any substances, materials or products on the property that may be environmental concerns, such as fuel or chemical storage tanks? (7.E)
A new version of the form takes effect on January 1, 2027 and adds a question about family burial grounds (RCW 64.06.020). A few sales are exempt from the form altogether, among them sales by the personal representative of an estate (RCW 64.06.010).
Sources
- RCW 64.06.020, the seller disclosure statement (Form 17) questionschecked
- RCW 64.06.010, sales exempt from the seller disclosurechecked
- Washington Pollution Liability Insurance Agency, heating oil tankschecked
- Seattle Public Utilities, your side sewerchecked
- Tacoma-Pierce County Health Department, septic Report of System Statuschecked
- Skagit County GIS, FEMA 100-year floodplain mapchecked
- Seattle Department of Construction and Inspections, environmentally critical areaschecked
- US Census Bureau, American Community Survey 2020-2024 5-year estimateschecked
