Side sewer inspection in Seattle: why it matters before you buy or sell

Why does a side sewer inspection matter in Seattle?

Because the pipe is yours, all the way to the street. Seattle Public Utilities' side sewer page says that if you own your home or building, you own your side sewer to the public sewer main under the street, including the part that extends beyond your property line. SPU's maintenance page tells owners to have the side sewer inspected before purchasing a property. A side sewer defect found after closing becomes the new owner's bill.

How does a camera inspection work?

A plumber, sewer inspection company or side sewer contractor runs a waterproof camera on a cable through the pipe, usually from a cleanout, and records video of the inside of the pipe. SPU's repair methods page adds two practical points:

• Cameras cannot see under water. If a line is blocked and not draining, the camera will not show much; inspections are most useful after the blockage has been cleared.
• Ask for a copy of the video. Most contractors can provide it on a USB drive or as a link. SPU says it is useful if you later file a claim with the city, want the city to review possible damage at the connection, or want to track deterioration over time.

Ask the inspector to note the footage of every defect and, if repairs are likely, to mark the spot on the ground.

How do you read the report?

SPU's side sewer defects page grades common defects and suggests what to do about each:

Defect	Minor	Moderate	Severe
Offset joints	No repair	Inspect after a few years	Repair; soil may erode into the pipe and cause voids
Sags	Less than 25% of pipe diameter, no repair	25 to 50%, inspect every two to five years	50% or more, repair
Cracks and fractures	Reinspect in three to five years	Inspect every one to two years and budget	Repair
Root intrusion	Reinspect in three to five years	Reinspect in three to five years	50% or more blocked: inspect every one to two years, clean routinely
Exposed aggregate (concrete pipe)	Reinspect in three to five years	Inspect every one to two years and plan repairs	With holes: replace as soon as found
Holes	SPU recommends repair for small, medium and large holes

SPU says side sewers are built at a slope of a quarter inch per foot so gravity carries debris, and that many Seattle side sewers are concrete pipe, where eroding cement is a common and critical defect. If one inspector calls for a full replacement and another sees only moderate defects, ask both to point to the footage behind their recommendation.

What records should you pull first?

Seattle keeps historic side sewer cards. SPU's maintenance page points owners to download the property's side sewer information, now in the city's Side Sewer Cards and Maps viewer. The card can show where the line runs and whether it is shared. SPU explains that when your pipe joins a neighbor's before reaching the main, you and your neighbor share maintenance and repair responsibility from that point to the main, and it recommends that neighbors agree on the scope of repairs and on the contractor. For a shared line, a defect in the shared section is a joint problem.

What does an inspection cost?

HomeGuide's 2026 sewer camera inspection guide, a national source, puts a sewer camera inspection at $125 to $500 for a home with a cleanout and $175 to $750 for a home without one, because the plumber may have to pull a toilet to get in. Adding a sewer scope to a home inspection costs $100 to $250. HomeGuide notes that a standard home inspection typically does not include a sewer camera inspection and recommends one for homes older than 20 years. For other prices, see our Seattle plumber cost guide.

What if you are selling?

Washington's seller disclosure statement for residential property, set out in RCW 64.06.020, asks whether the property is on public sewer, whether the house is connected to the sewer main, and whether there are defects in the plumbing system, including pipes, faucets, fixtures and toilets. A recent scope with video lets you answer accurately and gives buyers something concrete instead of a guess. If the scope shows problems, our repair options guide explains spot repairs, lining and pipe bursting, and that any repair in Seattle needs an SPU permit.

Who should do the inspection?

SPU says to choose a sewer inspection company, plumber or side sewer contractor. If the same company that inspects also bids the repair, consider a second opinion before a large job. Check any company in the L&I Verify tool and read our hiring guide.

How does this site fit in?

We are an independent guide operated by SWKM GmbH, not a contractor, and we do not perform plumbing work. If you want help, email us your neighborhood or ZIP code, the problem and a few photos. We reply by email with next steps and, where we know a licensed contractor for your area, an introduction. Run the checks on this page on anyone you hire, including anyone we mention.