Director's Rule

Title

Requirements for Drainage and Wastewater Service Number

DWW-110 Rev. no.

0

Responsibility

Development Services Office; Drainage and Wastewater Planning & Program Development Supersedes

N/A Pages

3

General Manager/CEO signature

/s/ Andrew Lee (electronic signature on file) Approval date

November 20, 2025 Effective date

January 1, 2026

A. PURPOSE

This Director's Rule establishes Seattle Public Utilities' (SPU) requirements to receive drainage and wastewater service. The requirements are documented in Water, Drainage, and Wastewater Availability Certificates (WACs) in response to certain applications for building or land use permits within SPU's direct service area, and new side sewer connections requests. Water availability is also documented in the WAC (refer to Director's Rule WTR-440).

B. DISCRETION

In limited or exceptional circumstances, and when it is in the best interests of the utility, SPU's General Manager/CEO or authorized designee, may modify or waive the requirements under this rule.

C. ORGANIZATIONS INVOLVED

The following agencies collaborate with SPU on WAC requirements or are jurisdictions where an SPU-issued WAC may be required:

City of Seattle, Seattle Public Utilities

City of Seattle, Department of Construction and Inspections

City of Seattle, Department of Transportation

Skyway Water and Sewer District

D. DEFINITIONS

Applicant. A parcel owner or owner's designee who is developing a parcel to be supplied with service or is seeking a land use permit. Applicant manages the project and communicates with the City.

Latecomer Agreement. A contract between the City and an owner of real property for the construction or improvement of water or sewer facilities that the City requires be constructed or improved as a prerequisite to further property development. Such latecomer agreements provide for the transfer of the water or sewer facilities to the City and for the later pro rata share reimbursement of costs to the owner as benefiting parcels subsequently connect to or use the facilities (SMC 21.63.020).

Parcel. A tract or plot of land, including unit lot subdivisions under SMC Title 23, Land Use Code. For the purposes of this rule, individual unit lots are considered separate parcels.

Side sewer. A privately owned and maintained pipe system that is designed to convey wastewater and/or drainage water to the public sewer system or approved outlet. This includes the pipe system up to, but not including, the tee, wye, or connection to the public main. (SMC 21.16.030).

Water, Drainage, and Wastewater Availability Certificate (WAC). The document SPU provides to applicants confirming if SPU water, drainage, and wastewater infrastructure exists to supply the parcel(s). The document identifies requirements, system improvements, and conditions necessary to provide service to the parcel. A WAC is required for most development projects in Seattle and in other jurisdictions within SPU's direct service area. WACs are issued based on the code requirements in effect upon application. A new application is required once an existing WAC has expired as stated on the certificate.

E. WATER, DRAINAGE, AND WASTEWATER AVAILABILITY CERTIFICATE

1. The WAC outlines provisional basic drainage, and wastewater service requirements and system improvements (public storm main extension, etc.) that are necessary for a proposed development project or a new side sewer connection to the public system. If the main sewer to which a parcel is required to connect to requires payment of a Latecomer Agreement (or other) fee at the time of WAC issuance, then the WAC also provides the reimbursement payment amount that may be due prior to connection to the drainage and/or wastewater main.

2. There are two ways to apply for a WAC. If your project:

a) Requires a building permit or a master use permit for a platting action from Seattle Department of Construction and Inspections (SDCI), SDCI will request a WAC for you as part of their process.

b) Does not require a building permit or a master use permit for a platting action from SDCI, apply directly to SPU.

3. An approved WAC is required for approval of building construction or land use permits within SPU's direct service area. There are four WAC statuses that may be issued depending on the following conditions:

a) Approved

The number and size(s) of side sewer requested, if known, for the project can be accommodated with no changes to the existing DWW infrastructure.

b) Approved for Existing Service

i. An existing side sewer shall be retained with no change; or

ii. The proposed project does not require drainage and/or wastewater service.

c) Not Approved

i. A drainage and/or wastewater main extension or other system improvement is required. In order to receive an Approved WAC, an Approved with Contract WAC will be issued when the applicant signs a contract provided by SPU to install the DWW extension or other required system improvement; or

ii. SPU may allow other system improvements in lieu of the standard DWW main extension requirement, in order to serve the parcel. These improvements may include but are not limited to alternative conveyance systems such as ditches, swales or curbs. These alternative improvements may not always be located adjacent to the parcel. If improvements to the collection system are required to provide service to the parcel, SPU shall describe the required changes to allow new service connections.

d) Approved with Contract

The parcel owner has signed a contract provided by SPU initiating a sewer main extension or other required DWW system improvements within SPU's conveyance system and has paid the associated charges.

4. The WAC provides information to allow for planning of the infrastructure improvements that may be necessary for the proposed project. If the proposed project has changes which impact the service requirements, the existing WAC shall no longer apply. The applicant must apply for a new WAC to allow SPU to evaluate the proposed changes.

5. Upon WAC expiration, a new WAC application is required. Changes to the project impacting the service requirements, existing infrastructure, or SPU requirements may result in different or additional requirements to receive service.

6. Conditions not specifically described in this Rule shall be evaluated on a case-by-case basis.

7. Regular changes to existing DWW main classifications may occur as SPU makes changes to its infrastructure or identifies incorrect designations.

8. An applicant may request a review of the requirements made on the WAC by applying for a Determination Review Request. Refer to Director's Rule ENG-430 for more information.

F. AUTHORITY/REFERENCES

Director's Rule 2011-004, Requirements for Design and Construction of Side Sewers (Drainage and Wastewater Discharges)

Director's Rule DWW-160, Restrictions on Use of Easements in Lieu of Drainage and Wastewater Main Extensions

Director's Rule DWW-210, Public Drainage System Requirements

Director's Rule ENG-420, Latecomer Agreements & Municipal Assessment Reimbursement Areas for Construction of Utility System Improvements

SMC 21.16, Side Sewers

SMC 21.63.020, Latecomer Agreements

SMC Title 21, Subtitle VIII, Stormwater Code

Revised Code of Washington (RCW) 19.27.097

RCW 35.91, Municipal Water and Sewer Facilities Act

RCW 35.92, Municipal Utilities