To assist Contra Costa County in its commitment to Equal Employment Opportunity, applicants are asked to voluntarily provide the following information. Contra Costa County only accepts online applications.When viewing a job posting for a currently open examination, you can select the option that says 'Apply'. An incomplete application packet may disqualify an applicant. Cover letter explaining your interest in the position. This letter is especially helpful if you're applying to a traditionally unrelated industry from your previous job. It does the following:. Click on View job listing to see more information on the job. Any cover letter should address the qualifications that you do have, in language that reflects the employer's field. Many schools offer career-guidance tools.