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Do Business With Us

Do Business With Us


Tips for Success

View Upcoming Capital Projects to learn more about anticipated contracting opportunities with King County.

Advertisements are published in the Seattle Times and the Daily Journal of Commerce. Or, register as a vendor to sign up for email notifications.

If you are invited by NAICS code to participate in a publicly advertised solicitation, you will automatically receive notice when addenda are issued.

If you were not invited to participate in the solicitation, you can view details of all advertised solicitations on the Solicitations Abstract webpage.

You must register in the E-Procurement Supplier Portal in order to access solicitations. Once registered you must login to "View Active Solicitations" from the homepage to search the solicitation you’re interested in. You must "Acknowledge Participation" in order to create a response and see addenda.

King County uses rosters for projects less than $350,000.  Roster projects are unadvertised; only roster members are invited to submit bids for roster projects. Because of their limited scope, roster projects are ideal for small firms.

Visit the Rosters page and begin the application process.

You can attend a pre-proposal meeting for advertised contracts to network with prime consultants. 

You can also visit our Solicitation Resources page to view lists of document holders and pre-proposal meeting attendees to find other businesses interested in a solicitation. 


Small Contractor and Supplier (SCS) certification is like a gold star next to your name, making  you eligible for special consideration by King County agencies and our partners (Sound Transit, Port of Seattle, and Seattle Colleges). 

Visit the SCS Certification page to learn who's eligible.

Visit the SCS Directory to search by category, NAICS, CSI, name or description.

Small Works Roster

Roster projects are not advertised; only roster members can bid. 

King County uses rosters for smaller projects (less than $350,000). 

Apply for roster membership

Contact Us

Phone: 206-263-9400

TTY Relay: 711

Fax: 206-296-7676