You can add your business to the state's vendor list and see bid opportunities at OneStop Vendor Information for selling to the state of Washington
You can go directly to add your business to Washington's Vendor's list by Add your business to the Vendor List for the State of Washington. Businesses on this list will receive email notification of bid opportunities.
Many cities require that any business which contracts with that city must pay prevailing or livable wage. This wage, which is set by the city, is generally higher than minimum wage.
Be sure to ask the city about any requirements before bidding on any job.