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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:
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
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: September 18, 2025 to September 30, 2025
Where: Virtual meetings
Please register HERE.
Regional Contracting Forum
Location: Muckleshoot Casino Resort - 2402 Auburn Way South Auburn, WA 98002
Date: September 17, 2025
Time: 8:00am – 3:00pn
Registration link: 2025 Regional Contracting Forum Tickets, Wed, Sep 17, 2025 at 8:00 AM | Eventbrite
Introduce your business to prime contractors, prime consultants and the region's largest government entities: City of Seattle, King County, Washington State Department of Transportation, University of Washington, Port of Tacoma, Washington State Office of Minorities and Women's Business Enterprises, Washington State Department of Enterprise Services, Sound Transit, Port of Seattle, City of Bellevue, City of Tacoma, Department of Social and Health Services, Department of Corrections, and others. Attendees have the opportunity to meet government contracting representatives and network with contractors, consultants, and suppliers all at one event.
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 am (PST)
Recording
Open house materials
- Presentation
- Attendance list
- Mouth of Duwamish Wet Weather Facilities Wet Weather Treatment Station Fact Sheet
- Mouth of Duwamish Wet Weather Facilities Conveyance Fact Sheet
- Mouth of Duwamish Wet Weather Facilities Storage Fact Sheet
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
- Event Flier
- Outreach and Networking Event Guide
- Opening Remarks Presentation
- King County Agency Presentations
- Contractor and Consultant Company Informational Slides
Agenda
| 8:30 AM |
Attendee check-in begins |
| 9:00 - 9:30 AM |
Opening Remarks: Lydia Reynolds, Strategic Business Operations Section Manager, Dept. Local Services, Road Services |
| 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