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Upcoming contract opportunities

This page hosts information for consultants and contractors interested in doing business with King County Wastewater Treatment Division (WTD).

King County WTD regional contractors and consultant opportunities

Updated quarterly

See also: Upcoming capital projects, Finance and Business Operations, Dept. of Executive Services

Invitation to bid

No invitations to bid at this time.

Request for proposal

Heavy Civil General Contractor/Construction Manager (GC/CM) Services for Mouth of Duwamish Combined Sewer Overflow (MDCSO) Wet Weather Treatment Station (WWTS) (KC001480)

KING COUNTY’S E-PROCUREMENT SUPPLIER PORTAL

The official advertisement (RFP KC001480) for this project will be published through King County’s E-Procurement system. To receive future notifications, please be sure your firm is registered in King County’s E-Procurement Supplier Portal. For registration information, please visit: https://kingcounty.gov/en/dept/executive-services/about-king-county/business-operations/finance-business-operations/procurement-payables/supplier-portal

Questions about the RFP? Contact Melissa Jordan, Contract Specialist (mejordan@kingcounty.gov)

The Mouth of Duwamish Combined Sewer Overflow (MDCSO) Program involves the construction of new facilities to manage combined sewer overflow events, improve water quality, and meet regulatory requirements. The program consists of a new Wet Weather Treatment Station (WWTS), associated influent and effluent conveyance systems, new diversion structures, and a storage tank at Chelan to accommodate peak flows. The WWTS has a design capacity of 228240 million gallons per day (MGD) (278 MGD at peak) and includes critical infrastructure for screening, sedimentation, UV disinfection, and solids handling. The site is located approximately 2,000 feet from the Duwamish Waterway and includes significant geotechnical and utility coordination challenges.

Reference Material Files: Proposed Facilities Fact Sheet

Prospective proposers can view more details at: https://kingcounty.gov/procurement/solicitations

Complete Solicitation Documents, including project details, specifications, and contact information are available on the Procurement and Payables web page at: https://kingcounty.gov/procurement/supplierportal

Request for information

Mouth of Duwamish Combined Sewer Overflow (MDCSO)

Request for Information

KING COUNTY’S E-PROCUREMENT SUPPLIER PORTAL

WTD has published four (4) Requests for Information (RFI(s)) through King County’s E-Procurement system. To receive future notifications, please be sure your firm is registered in King County’s E-Procurement Supplier Portal. For registration information, please visit: https://kingcounty.gov/en/dept/executive-services/about-king-county/business-operations/finance-business-operations/procurement-payables/supplier-portal

PURPOSE of RFI 1: King County Wastewater Treatment Division (WTD) released the first RFI to provide initial project information for Mouth of Duwamish Combined Sewer Overflow (MDCSO) Wet Weather Facilities, located in Seattle, WA. The executive summary of the initial RFI is linked below:

PURPOSE of RFI 2: WTD released the second RFI to provide feedback and updated project information for MDCSO Packages 1 (Wet Weather Treatment Station) and 2 (Effluent Conveyance), located in Seattle, WA. The executive summary of the second RFI is linked below:

The Project Review Committee (PRC) approved the Wet Weather Treatment Station project on May 22, 2025. The procurement approach will be GC/CM.

PURPOSE of RFI 3: WTD released the third RFI to request feedback for the Effluent Outfall and Conveyance/Influent Conveyance systems which, with the future Wet Weather Treatment Station, will function as a complete system. The executive summary of the third RFI is linked below.

The Project Review Committee (PRC) approved the Influent Conveyance, Effluent Conveyance and Outfall on July 24, 2025.

PURPOSE of RFI 4: WTD released the fourth RFI to request feedback for the Chelan Wet Weather Storage project which will function as a storage facility for overflow. The executive summary of the fourth RFI is linked below.

The Project Review Committee (PRC) will review the Chelan Wet Weather Storage on September 25, 2025. The procurement approach will be GC/CM pending PRC approval.

Questions about the Project details? Contact Steve Tolzman, WW Capital Program Manager (steve.tolzman@kingcounty.gov, 206-477-5851), OR Trisha Roth (troth@kingcounty.gov, 206-263-1964)

PROJECT LOCATION: Mouth of Duwamish River, generally the area south of downtown Seattle, WA

PROJECT BACKGROUND: King County WTD will delivery essential infrastructure to control wet weather sewer overflows in the Duwamish River.

CONSTRUCTION ESTIMATE: Expect multiple contracts totaling greater than $2 Billion.

EQUITY AND SOCIAL JUSTICE GOALS: KC will establish a minimum required level for the participation of small and diverse businesses for these contracts. The goals will be expressed as a percentage of the total contract value to be performed by OMWBE certified firms. To ensure success at meeting the diverse small business goals and to promote support and mentoring of small businesses, KC will also require the submission of an Equity and Social Justice (ESJ) Innovation Plan.

POTENTIAL FUNDING SOURCES: Washington State Revolving Fund, Water Infrastructure Finance and Innovation Act (WIFIA). Specific funding sources will be determined as the projects evolve.

Calendar

Informational Open House: Upcoming Contracting Opportunities - King County Wastewater Treatment Division

King County Wastewater Treatment Division (WTD) is hosting a virtual Informational Open House for interested firms to learn about upcoming projects and events. To encourage early teaming arrangements, we hope interested firms attend.

Event Date/Time

September 4, 2025, at 10:00 AM (PST)

Duration: Approx. 1 hour
MS Teams Meeting Link (Registration is required): Register HERE
Link: https://tinyurl.com/WTDOpenHouse-09042025
Once registered, you will receive an email confirmation that will include the meeting link with the option to save a meeting reminder on your calendar.

About the event

WTD will provide schedule updates on some of our collaborative delivery projects as well as a number of upcoming construction, consulting and work order contracts and highlight upcoming projects. A brief description of some of the projects presenting at this Open House are below:

Small Generators Replacement Group 1: This project provides engineering and related services to King County Department of Natural Resources and Parks, Wastewater Treatment Division (WTD) to identify and evaluate alternatives to replace small standby power generators and associated systems at 16 regulator or outfall stations. The 16 stations have been divided into three groups, this project is specifically for Group 1.

Brightwater Operations Center Roof & HVAC Replacement: This project will replace the roof and associated heating, ventilation, and air conditioning (HVAC) equipment on top of the Brightwater Treatment Plant Operations Center (BOC) (92,000SF). The project will also add a solar panel system and remove decommissioned equipment that is no longer operational.

Informational Open House: Upcoming Contracting Opportunities - King County Wastewater Treatment Division

King County Wastewater Treatment Division (WTD) is hosting a virtual Informational Open House for interested firms to learn about upcoming projects and events. To encourage early teaming arrangements, we hope interested firms attend.

Event Date/Time

June 24, 2025, at 1:00 PM (PST)

Recording

Open house materials

About the event

WTD will provide schedule updates on some of our collaborative delivery projects as well as a number of upcoming construction, consulting and work order contracts and highlight upcoming projects. A brief description of projects presenting at this Open House are below:

Mouth of Duwamish Combined Sewer Overflow (MDCSO) Program: King County Wastewater Treatment Division has initiated the Mouth of Duwamish Combined Sewer Overflow (MDCSO) Program to implement an integrative solution to control the discharge of five Combined Sewer Overflows (CSO) outfalls that occur during wet weather events in Seattle, flowing to the mouth of the Duwamish River. The project area is in the SODO neighborhood and includes sections of the Elliott Bay shoreline within Seattle and the east and west waterways of the Duwamish River on either side of Harbor Island. The five outfalls (Chelan, Hanford #2, Lander, Kingdome, and King Street) are all located in the Duwamish Waterway. The program will build infrastructure to convey, store and treat combined sewer flow during storm events to control CSOs per regulations.

Sammamish Plateau Diversion (GC/CM): This project will address regional conveyance system capacity needs by diverting flows out of the South Lake Sammamish Planning Area north. Diverting flows northward will alleviate capacity needs at several King County conveyance facilities.

South Treatment Plant (STP) Dissolved Air Flotation Tanks (DAFT) Rehabilitation (ITB): The County’s Wastewater Treatment Division (WTD) will replace DAFTs 1 through 6 process equipment and covers at the STP. The DAFTs co-thicken primary sludge and waste activated sludge. Work includes performing demolition and replacement of the DAFT metal equipment components with new 316 Stainless Steel equipment, conversion of rail track system to cantilever system, new flat aluminum covers, ventilation system upgrades, access improvements, and pilot testing a sludge blanket level monitoring device. The equipment vendor package will include bridge beams, center column with internal motor, two rake arms, eight skimmer arms, two float boxes, and effluent Launder pipe.

Contractor 1:1 Meetings

King County Wastewater Treatment Division (WTD) will be hosting opportunities for contractors and consultants to meet individually with WTD staff to discuss specific projects of interest. Below is a registration form to provide WTD with your firm’s date(s) of availability and project(s) of interest. We look forward to meeting your team!

When: May 6, 2025 – May 14, 2025

Where: Virtual meetings

Please register HERE.

King County Contractor Outreach and Networking Event

When: April 21, 2025
Time: 9:00am – 2:00pm
Location: Muckleshoot Events Center, 2402 Auburn Way S, Auburn, WA 98002

Join us at the event to:

  • Network with prime contractors and consultants and small, M/WBE firms
  • Participate 1:1 Contractor-Subcontractor meetings
  • Learn about upcoming projects from multiple King County agencies such as WTD, Parks, Metro, Roads, and FMD to name a few

Event resources

Agenda

 8:30 AM

Attendee check-in begins
Foyer

 9:00 - 9:30 AM

Opening Remarks: Lydia Reynolds, Strategic Business Operations Section Manager, Dept. Local Services, Road Services
Keynote Speaker: Marissa Aho - Assistant County Executive, Executive Climate Office
Medicine Creek Conference Room

 9:30 AM - 2:00 PM Networking
Medicine Creek & White River Conference Rooms
 10:00 AM - 2:00 PM King County Project Presentations
Executive Climate Office
Facilities Management Division (FMD) - Harborview Bond
Road Services Division
Metro
Solid Waste Division (SWD)
Parks
Water and Land Resources Division (WLRD)
Wastewater Treatment Division (WTD)
White River Conference Room
 10:00 AM - 12:00 PM 1:1 Contractor Networking Meetings – Group 1, General Contractors
Green River Conference Room
 12:00 - 2:00PM 1:1 Contractor Networking Meetings – Group 2, Consultants
Green River Conference Room
 

Informational Open House: Upcoming Contracting Opportunities - King County Wastewater Treatment Division

Event Date/Time

March 4, 2025, at 1:00 PM (PST) 

Recording

Open house materials

About the event

King County Wastewater Treatment Division (WTD) is hosting a virtual Informational Open House for interested firms to hear information about some of our upcoming projects and events. To encourage early teaming arrangements, we hope interested firms attend. 

A brief description of events at this Open House are:

In-Person Networking Event: You won’t want to miss this in-person event! King County Wastewater Treatment Division (WTD) will be hosting a networking opportunity for prime contractors and consultants and small, women and/or minority owned firms to connect on upcoming projects. Additionally, WTD along with other King County agencies such as Solid Waste, Metro, Parks and others will be there to discuss upcoming projects. Networking Event will be held on April 21. 

Project Updates: We will be providing schedule updates on some of our collaborative delivery projects as well as a number of upcoming construction, consulting and work order contracts.

Contractor 1:1 Meetings

King County Wastewater Treatment Division (WTD) will be hosting opportunities for contractors and consultants to meet individually with WTD staff to discuss specific projects of interest. Below is a registration form to provide WTD with your firm’s date(s) of availability and project(s) of interest. We look forward to meeting your team!

When: January 21, 2025 – January 29, 2025

Where: Virtual meetings

Please register HERE.

Doing business with the county

The procurement and contract services section (PCSS) website is designed to assist users who do business with King County. The web site provides procurement and contract information for:

  • Construction
  • A&E and professional services
  • Technical services
  • Goods and services
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