During construction, workers may pump groundwater or stormwater away from the site. This process is called dewatering.
Typically, this water is treated and sent to a surface water body, either directly or through a storm drain. If the treated water does not meet water quality criteria; or if direct or indirect discharge is not available, it may be possible to send the treated water to the sanitary sewer. However, you must get permission from King County and your local sewer agency to send this treated water to the sewer.
Who needs formal authorization from King County?
|Authorization not required|| Authorization required
(see process below)
|Most construction projects discharging to sanitary sewers in King County’s Wastewater Service area (including combined sewers that carry stormwater and sewage in the older parts of Seattle) need approval.|
How to get formal authorization
- Contact the local sewer agency. Confirm they accept water from construction sites. Confirm the location and conditions for discharging to their system.
- Select your King County construction dewatering application (general or individual).
- Download, complete, print and sign your application. Scan your signed application and submit it to King County via email: info.KCIW@kingcounty.gov
- Contact the local sewer agency for permission to connect to their system and any additional requirements.
NOTE: If the proposed dewatering discharges directly to a King County sewer, you will also need to get approval from the King County Local Public Agency (LPA) Program to use the facility for the discharge.
Allow enough time! The General Authorization Process may be complete as quickly as 3-10 working days. The Individual Authorization Process takes about 1 to 3 months depending on the complexity of the project. The cost of General Authorization is a set fee. The cost of Individual Authorization or permit depends on project complexity. This fee is not refundable and must be paid even if your project plans change and you no longer want to discharge to the sewer system. Click here for information about fees.
Select your King County application
KCIW offers two types of authorizations for discharging construction water to sanitary sewers:
|General Authorization Application||Individual Authorization Application|
You may be able to use the General Authorization Application for Construction Dewatering if your project meets all of the following criteria:
Applying for a General Authorization is easier and requires less documentation (no exhibits) than an Individual Authorization, and no reporting is necessary once the General Authorization is approved.
If your project does not meet all four criteria, you must use the Individual Authorization Application for Construction Dewatering .
Your permit or letter of authorization to discharge wastewater into the sewer system may require self-monitoring. View and download the self-reporting forms.
The General Construction Dewatering Authorization does not require reporting.