Side Sewer Permit Seattle: What Homeowners Need to Know

The “side sewer” in Seattle is the private sewer lateral — the pipe that runs from your house to the public sewer main in the street. Any repair or replacement of this line requires permits from two agencies: SDCI (Seattle Department of Construction and Inspections) and SPU (Seattle Public Utilities). Here’s how the permit process works and what homeowners can expect.

What Is a “Side Sewer” in Seattle?

The side sewer is the private portion of the sewer system connecting your home to the public main.

In Seattle, the terminology works like this:

• Public sewer main: Owned and maintained by Seattle Public Utilities (SPU). Runs under the street. SPU’s responsibility.
• Side sewer (private sewer lateral): Runs from your house to the public main connection point. The homeowner owns and is responsible for this pipe — including repair costs when it fails.
• Connection point: Where the private lateral connects to the public main. Both SDCI and SPU have jurisdiction at this point.

Typical side sewer problems that require permitted repair:
– Root intrusion causing blockage or collapse
– Pipe deterioration (cast iron corrosion, clay pipe cracking, concrete pipe joint failure)
– Sags or belly in the line causing solids buildup
– Complete collapse
– Offset joints from soil movement

When a Side Sewer Permit Is Required

Any of these activities on the private sewer lateral requires a permit:

• Repair of a section of the lateral
• Full replacement of the lateral (trench or trenchless)
• Trenchless lining (CIPP — cured-in-place pipe lining)
• Trenchless pipe bursting
• Disconnecting or reconnecting to the public main
• New connection (new construction, ADU with sewer service)
• Abandoning an existing connection

Simple drain cleaning or camera inspection:
Hydrojetting or snaking a blocked lateral and camera inspection alone don’t require a permit. If the inspection reveals damage requiring repair, the repair work requires a permit.

Two Agencies: SDCI and SPU

Side sewer work involves two separate city agencies with different roles:

SDCI (Seattle Department of Construction and Inspections):
– Issues the side sewer permit
– Conducts plumbing code inspection of the lateral work
– Enforces the Seattle Plumbing Code requirements for pipe materials, slope, and installation

SPU (Seattle Public Utilities):
– Inspects the connection point at the public sewer main
– Confirms the connection meets SPU’s standards
– Issues SPU’s own approval at the connection
– Manages sewer main capacity and connection records

Both approvals are required:
Work cannot be backfilled until SDCI inspects the lateral work and SPU inspects the connection. Your plumber coordinates with both agencies.

The Side Sewer Permit Process

Step 1: Camera inspection of the existing lateral
Before applying for a permit, most plumbers will video-inspect the existing lateral to document its condition, identify the failure, and determine the scope of repair. SPU often requires a pre-repair video as part of the permit documentation.

Step 2: Permit application (SDCI)
The contractor applies for a side sewer permit through the Seattle Services Portal (seattle.gov/sdci). Application includes:
– Project address
– Description of work (repair, replacement, trenchless lining, etc.)
– Scope and estimated value
– Lateral video documentation (required or requested)

Step 3: Permit issuance
SDCI reviews the application and issues the permit. Typical timeline: 3–7 business days for standard residential side sewer work.

Step 4: Work is performed
Repair or replacement is done. For trench work, the trench is left open for inspection. For trenchless lining, the plumber is ready for inspection before work is considered complete.

Step 5: SDCI inspection
SDCI inspector visits to verify the lateral work meets code. For open-trench work, the pipe is inspected before backfilling.

Step 6: SPU inspection
SPU schedules their own inspection of the connection at the public main. This is the step that often takes the most time — SPU inspection scheduling can run 5–10 business days from request.

Step 7: Backfill and close-out
After both SDCI and SPU have approved the work, the trench is backfilled, surfaces are restored, and the permit is closed.

SPU Video Inspection Requirements

SPU typically requires video documentation of side sewer work:

Pre-work video:
Documents the existing condition of the lateral before repair. This establishes a baseline and confirms the failure being addressed.

Post-work video:
Confirms proper installation after the repair or replacement is complete. For trenchless lining (CIPP), the post-lining video confirms the liner is properly installed, seams are sealed, and no wrinkles or voids are present.

Who conducts the video:
The plumber typically performs the camera inspection as part of the project. Alternatively, SPU may conduct their own camera inspection at the connection point as part of their inspection.

Why video matters:
For trenchless work especially, video is the only way to verify what’s happening inside the pipe. Post-lining video is the quality check — it documents that the work was done correctly before the street or yard is restored.

Side Sewer Permit Fees in Seattle (2026)

Permit fees are calculated by SDCI based on project scope and valuation. These are separate from SPU fees, which may apply for connection inspection.

Total project cost context:
The permit fee is a small fraction of total side sewer project cost. Full lateral replacement in Seattle: $8,000–$20,000+. Trenchless lining: $6,000–$15,000 depending on length and conditions. The permit is not where to cut costs.

FAQ

Q: Do I need a permit to repair my side sewer in Seattle?
A: Yes — any repair or replacement of the private sewer lateral requires a side sewer permit from SDCI and coordination with SPU for inspection at the public sewer connection. Simple drain cleaning without repair does not require a permit.

Q: Who is responsible for the side sewer in Seattle?
A: The homeowner is responsible for the private sewer lateral — the pipe running from the house to the public sewer main. This includes all repair and replacement costs. SPU is responsible for the public sewer main in the street.

Q: How long does the side sewer permit process take in Seattle?
A: SDCI permit issuance: 3–7 business days. SPU inspection scheduling: 5–10 business days is typical. Plan for 2–3 weeks from permit application to final approval, not including the work itself. Actual digging and pipe work may take 1–3 days depending on the project.

Q: Does trenchless sewer lining require a permit in Seattle?
A: Yes — trenchless CIPP lining and pipe bursting both require a side sewer permit from SDCI and SPU approval. The permit requirement applies regardless of the repair method.

Q: How much does side sewer work cost in Seattle?
A: Permit fees: $300–$700 for most residential work. Total project cost depends heavily on scope: spot repair ($2,000–$6,000), full trench replacement ($10,000–$20,000+), trenchless lining ($6,000–$15,000). Camera inspection to diagnose the problem first helps determine which approach applies.