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King County Washington home

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) Chelan Wet Weather Storage

KING COUNTY’S E-PROCUREMENT SUPPLIER PORTAL

The official advertisement (RFP KC001590) 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 Leeann Snyder, Contract Specialist, lsnyder@kingcounty.gov, 206-263-3517.

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. This Heavy Civil GC/CM project includes preconstruction and construction for the MDCSO Chelan Wet Weather Storage. The Chelan Wet Weather Storage Project will serve combined sewer basins west of the Duwamish River. These basins receive both sanitary wastewater and stormwater. During rainfall events, flow in the combined sewer may exceed the sewer capacity, resulting in overflows to nearby waterbodies. The project includes construction of several new facilities including a 7-million gallon below grade combined sewer overflow (CSO) storage tank, a diversion structure, demolition and replacement of the Chelan regulator station, and installation of approximately 2,600 lineal feet of open-cut and trenchless (e.g., microtunneling and/or pipe ramming) influent 60-inch pipe.

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

Heavy Civil General Contractor/Construction Manager (GC/CM) Services for Mouth of Duwamish Combined Sewer Overflow (MDCSO) Influent Conveyance, Effluent Conveyance and Outfall (IECO)

KING COUNTY’S E-PROCUREMENT SUPPLIER PORTAL

The official advertisement (RFP KC001493) 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 procurement? Contact Jenny Sebero, Contract Specialist (jsebero@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 Influent Conveyance scope consists of 5,516 feet of piping to route combined sewer and stormwater into the future Wet Weather Treatment Station (WWTS). The WWTS is a separate project/contract. This includes capacity upgrades to existing regulator structures, achieved through upsized gates and adjacent pipe replacement. The system will reroute flows from the main trunk lines and upstream holding areas into newly constructed regulator stations, regulating discharge into the WWTS. Of the total length, 1,492 feet will be constructed via microtunneling, with the remainder installed using open cut or trenchless methods. Key constructability considerations include flow diversion of existing pipe for connection, permitting complexity and utility coordination, instrumentation and control coordination, physical and contractual interfaces, geotechnical/environmental challenges, construction market conditions, cost uncertainty and equipment procurement.

The Effluent Conveyance and Outfall scope includes approximately 1,240 feet of piping to convey treated effluent from the WWTS to the Duwamish River. This involves relocation of utilities, open trench installation, and surface restoration. A 360-foot section will be constructed using trenchless technology, supported by two shafts. A new pump station will be built to convey treated water, with in-water work including a diffuser installed in a sheeted trench, fish habitat restoration within the vicinity of the outfall trench, and the use of anchored barges for excavation support. In addition to the items identified for Influent Conveyance, key constructability considerations include outfall cleanup and remediation within a Superfund site, marine (in-water) work including anchored barges for excavation equipment and materials storage, environmental approvals and specific requirements (seasonal fishing windows).

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

 

 

Progressive Design Build Services for South Interceptor Rehabilitation Project (KC001390)

As part of RFP Addendum 1, Progressive Design Build Services for South Interceptor Rehabilitation Project (KC001390), the following are being provided to the general public and as reference documents to the shortlisted firms. The listed reference documents are for general information only and shall not be relied upon for design development.

Reference Materials:

Flow Monitoring

Video

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

Contact: Melissa Jordan, Contract Specialist, at mejordan@kingcounty.gov.

Request for information

No requests for information at this time.

Calendar

King County Contractor Outreach and Networking Event

Thank you for attending our third annual King County Contractor Outreach and Networking Event!

We had a fantastic turnout with over 800 attendees representing nearly 400 different businesses – our biggest event yet!

Additional information from the event can be found below:

We value your feedback! Please fill out our feedback form so we can continue to add features and make improvements to future events.

Check out a short video from the event: LinkedIn  Facebook  Instagram

 

flyer for 2026 King County Contractor Outreach and Networking Event on April 15, 2026.

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 22 to February 4, 2026

Where: Virtual meetings

Please register HERE.

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

January 15, 2026, at 10:00 AM (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 some of the projects presenting at this open house are below:

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.

South Plant Treatment & Electrical Improvements: Eight Projects all delivered under a single construction project. Undergoing evaluation for collaborative delivery.

Sammamish Plateau Diversion: 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 Plant DAFT Tank Rehabilitation: 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.

Additionally, East Ship Canal Engineering RFP, Minor Asset Management Projects (MAMs) and Capital Asset Management Projects (CAMPs).

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

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.

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