Seattle Side Sewer Permit 2026: Updated Requirements and Process

If you are planning sewer repair, side sewer repair, side sewer installation, or a full replacement in Seattle, yes, a Seattle side sewer permit is often required.

As of October 1, 2025, Seattle Public Utilities handles these permits instead of SDCI, and you now apply online through the Seattle Services Portal under Public Utilities – Development Services. Seattle’s side sewer permit covers work on private property and, in many cases, work in the public right of way, with separate SDOT approval also needed when your project reaches the street.

We know this topic can feel more complicated than it should. You just want to know: do I need a permit to replace my sewer line, where to apply, what documents you may need, and what can slow your sewer project down.

This guide walks you through the Seattle side sewer permit requirements 2026 homeowners should know before starting any sewer work.

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Quick answer on Seattle side sewer permit requirements in 2026

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Here is the short version.

• A side sewer permit is required for many types of sewer construction, repair, alteration, capping, removal, and connection work in Seattle.
• As of October 1, 2025, Seattle Public Utilities manages side sewer permitting and side sewer inspections.
• You apply through the Seattle Services Portal by selecting Public Utilities – Development Services and then Side Sewer Permit SPU.
• A permit is generally valid for 18 months.
• If your project involves work in the public right of way, Seattle says a separate additional permit from SDOT is also required.
• Permit fees vary by project scope, and SPU lists common repair permit costs starting around a few hundred dollars.

That is the core answer, but the details matter. The difference between work on private property and work in the street can change your permit path, your timeline, and your inspection requirements.

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What a side sewer is and why the permit matters

A side sewer is the privately owned pipe system that carries wastewater from your sinks, toilets, tubs, and drains to the public sewer system. In some situations, it can also carry drainage water to an approved outlet. If you own the property, Seattle says you own your side sewer all the way to the connection at the public main.

That ownership point matters because a lot of homeowners assume the city handles every underground sewer issue automatically. Usually, that is not how it works. If the problem is in your entire side sewer, including the section outside the building footprint up to the public connection, repair responsibility is usually on you as the property owner.

The city of Seattle side sewer permit exists for a good reason. It helps protect:

• Public health
• Safety standards
• The public sewer system
• Nearby public infrastructure
• Proper inspection and construction quality

From our side, this is one of those permits that is easy to underestimate until a project stalls. When underground work starts without the right permit requirements, corrections get expensive fast.

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Who handles the Seattle side sewer permit now

One of the biggest 2026 updates is simple but important: Seattle Public Utilities now manages side sewer permits. Seattle’s official permit instructions say that, as of October 1, 2025, SPU issues these permits instead of the Seattle Department of Construction and Inspections. Seattle also says SPU now conducts sanitary and wastewater plan review, side sewer permitting, and side sewer inspections.

That matters because older pages, old contractor advice, and older blog posts may still point you toward SDCI. For current Seattle side sewer permit requirements 2026, the source you want is SPU.

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Do you need a permit to replace your sewer line in Seattle

In many cases, yes. Seattle Public Utilities says a side sewer permit is required to:

• connect a property or building to the public sewer system
• construct or make repairs, alterations, or additions
• abandon, remove, or cap a sanitary or drainage side sewer
• inspect required onsite drainage control facilities

That means the answer to "do I need a permit to replace my sewer line" is usually yes if the work involves your side sewer. It also means a sewer permit may apply even when the work is not a full replacement.

A routine side sewer repair can still require a permit. SPU even lists a specific Side Sewer Permit for Repair for projects where a pipe or external sewer fixture needs to be repaired or replaced.

A few common examples where a sewer permit is required include:

• replacing a damaged pipe section
• repairing a broken cleanout
• adding to an existing sewer connection
• doing side sewer installation for new construction
• capping an old sewer line
• work that reaches the public right of way

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How the sewer permit application works in Seattle

The current side sewer permit application process is online. Seattle’s official instructions say to go to the Seattle Services Portal, choose Public Utilities – Development Services, and then select Side Sewer Permit SPU. From there, you search the project address, choose the correct address, and enter your project details.

Here is the basic process we would follow:

1. Confirm the scope of the project

• Figure out if this is sewer repair, replacement, alteration, capping, or new sewer installation.

1. Use the Seattle Services Portal

• Start the sewer permit application under Public Utilities – Development Services.

1. Enter the project address carefully

• Seattle specifically tells applicants to make sure the address is within Seattle city limits and to select the correct address if more than one appears.

1. Add a detailed description

• Your scope of work should clearly explain the side sewer work you want to do. For new construction, Seattle says the description of work must match the approved construction plans.

1. Upload required documents if your project needs them

• Some projects, especially new construction or shared side sewer situations, need additional recorded or supporting documents.

1. Track the permit number and inspection steps

• Keep your permit number, inspection schedule, and approvals in one place.

This is where a lot of applications get delayed. Usually it is not because the project is impossible. It is because the address, scope, or documents do not line up cleanly.

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Required documents homeowners may need

Not every project needs the same paperwork, which is why permit requirements can feel vague at first. Seattle says that for new construction, and depending on the scope of the project, you may need to submit documents as part of your side sewer permit application.

Examples Seattle lists include:

• Memorandum of Drainage Control
• Side Sewer Easement Agreement
• Side Sewer Joint Use and Maintenance Agreement
• Side Sewer Release and Indemnification Agreement
• Certificate or Attestation of Mailing Notification
• Side Sewer Evaluation and Certification Form

These are especially relevant when:

• a side sewer crosses another property
• more than one property or dwelling shares a side sewer
• an existing side sewer is being reused
• a project does not meet standard code conditions and needs special acknowledgment

So if you are a property owner dealing with a simple repair, you may have a lighter process. If you are dealing with shared lines, new development, or unusual site conditions, the document list can grow quickly.

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Private property vs public right of way

This is one of the most important distinctions in the whole process.

Seattle says a side sewer permit covers proposed side sewer work on private property and within the public right-of-way. But Seattle also says that if there is any work in the public right of way, such as excavation or even equipment staging, a separate additional permit from SDOT is required.

In plain English, that means:

If your sewer work stays on private property

You may only need the SPU side sewer permit, depending on the project scope.

If your sewer work reaches the street or right of way

You may need:

• the SPU side sewer permit
• an SDOT permit application or Street Use approval
• extra coordination for traffic, excavation, restoration, or access

This is one area where we always recommend slowing down and double-checking. A project can look like a straightforward side sewer repair until the actual line location shows that part of the work enters the street.

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Key 2026 requirements homeowners should know

Beyond the basic application process, a few specific 2026 details matter.

1. The permit is generally valid for 18 months

Seattle Public Utilities says a side sewer permit is valid for 18 months, unless you renew it or make prior arrangements with SPU.

2. Fees vary based on scope

Seattle says side sewer permit fees vary based on the scope of work. SPU’s current page gives examples such as:

• Sanitary repair permit on private property generally costs $280
• Drainage repair permit on private property generally costs $375
• An addition or alteration permit generally costs $375
• New construction side sewer permit fees can total $750 for sanitary and storm, plus any recording document fees

3. King County capacity charge may apply

For properties connecting to the sewer system on or after January 1, 2026, King County says the 2026 capacity charge is $77.99 per residential customer equivalent per month, with the actual monthly amount depending on home size or property type.

King County also says this charge applies to properties whose sewage flows to a King County treatment plant and that connect to the system after February 1, 1990.

That does not mean every repair project automatically triggers a new capacity charge. It is project-specific, so this is one of those items we would verify early if your work involves a new connection, reconnection, addition, or change of use.

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Technical standards that can affect approval

This is where homeowners often hear a few rules from a contractor but do not know which ones actually matter.

Seattle materials tied to side sewer design and construction indicate key standards such as:

• 4-inch minimum pipe size for single-family side sewer work
• 2% minimum grade
• about 1/4 inch fall per foot
• no backfilling before inspection

Seattle also notes that one recorded agreement may be required when a side sewer does not meet standard code conditions, and it gives a typical example of pipes built at less than a two percent slope.

From a practical point of view, this means your sewer contractor and your permit details need to agree on the basics. Pipe size, slope, and inspection timing are not minor details. They are approval details.

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Why no backfilling before inspection matters

This one catches people off guard. Once a trench is closed, inspectors lose a direct view of the installation. If work is backfilled too early, you can end up reopening the trench, delaying final inspection, and adding cost to the project.

That is why inspection timing is such a big part of the side sewer permit requirements conversation. Seattle’s permit structure includes inspections as part of the process, and the city’s technical guidance points to inspection before backfill as a key requirement.

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Should you hire a licensed contractor

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Seattle defines the applicant broadly and says anyone can apply for a side sewer permit, including a property owner, owner’s agent, builder, or side sewer contractor.

Even so, for most real-world projects, working with a licensed contractor is the safer path. A contractor who knows Seattle sewer code, inspection sequencing, and right-of-way rules can help you avoid the most common errors, like:

• using the wrong permit path
• submitting a weak or incomplete scope description
• missing required documents
• underestimating right-of-way impacts
• scheduling work before inspection approval

We have seen this pattern in a lot of construction-related permitting. The job itself may be straightforward, but the paperwork and sequencing are where projects lose momentum.

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Common mistakes that delay side sewer permits

If you want the smoother route, avoid these:

Using outdated agency information

SPU now handles side sewer permits, not SDCI. Starting in the wrong place wastes time.

Entering the wrong address

Seattle’s application instructions specifically call out choosing the correct address in the portal.

Writing a vague project description

A weak detailed description can create questions and review delays.

Forgetting ROW coordination

If your work touches the street or the public right, you may need SDOT approval too.

Backfilling too early

This can derail your final inspection and slow final approval.

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A simple homeowner checklist for 2026

Before you start your sewer project, here is the checklist we would use:

• Confirm that your project involves a side sewer permit
• Check if the work is on private property, in the public right of way, or both
• Apply through the Seattle Services Portal
• Select Public Utilities – Development Services
• Double-check the project address
• Prepare a clear detailed description
• Ask whether any required documents apply to your site
• Confirm if an SDOT permit application is needed
• Verify inspection timing
• Do not backfill before inspection
• Keep your permit number, fees, and approval records organized

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Final thoughts

The biggest takeaway for 2026 is this: Seattle side sewer permits are now handled by Seattle Public Utilities, and a permit is required for many types of side sewer work, including repair, installation, replacement, capping, removal, and certain connection-related work.

Homeowners apply through the Seattle Services Portal, projects involving the public right of way may also need SDOT approval, and permits are generally valid for 18 months. For current fees, project-specific requirements, and inspection details, it is best to confirm directly with Seattle Public Utilities before work begins.

Need help with sewer work and permits? Aces Four provides sewer services and can also help guide you through the Seattle side sewer permit process so your project stays on track. Contact Aces Four to get started.

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FAQs

1. Who handles Seattle side sewer permits in 2026?

As of October 1, 2025, Seattle Public Utilities (SPU) handles Seattle side sewer permits, plan review, and side sewer inspections instead of SDCI. Homeowners applying in 2026 should use SPU’s current process, not older SDCI instructions.

2. Do I need a permit to replace my sewer line in Seattle?

In many cases, yes. Seattle requires a side sewer permit for many types of side sewer work, including repair, installation, replacement, alterations, capping, removal, and certain connection-related work on private property or within the public right-of-way.

3. How do I apply for a Seattle side sewer permit?

You apply online through the Seattle Services Portal. Seattle Public Utilities instructs applicants to choose Public Utilities – Development Services, then select Side Sewer Permit SPU, search the project address, and complete the application with the required project details.

4. Does a Seattle side sewer permit cover work on private property and in the street?

Yes. Seattle says a side sewer permit covers proposed side sewer work on private property and/or within the public right-of-way. If the project includes work in the street or other right-of-way areas, a separate additional SDOT permit may also be required.

5. How long is a Seattle side sewer permit valid?

A Seattle side sewer permit is generally valid for 18 months. If your project takes longer, you should check with Seattle Public Utilities about renewal options or any additional requirements before the permit expires.

6. What documents might be required for a side sewer permit application?

Required documents vary based on project scope. Seattle says some side sewer permit applications, especially for new construction or shared side sewer situations, may require supporting documents such as easement agreements, joint use agreements, notification forms, or evaluation and certification forms.

7. What technical standards matter for Seattle side sewer approval?

Seattle’s side sewer design guidance includes a 4-inch minimum pipe size for single-family side sewers, a 2% minimum grade or about 1/4 inch of fall per foot, and a rule against backfilling before inspection. These standards can affect whether the work passes inspection and receives final approval.

8. Is there a King County capacity charge in 2026?

For applicable new sewer connections, King County’s 2026 capacity charge is $77.99 per residential customer equivalent per month. This charge applies to qualifying properties connecting to the sewer system on or after January 1, 2026, so homeowners should confirm whether it applies to their specific project.