What is an employer's window to conduct post and pre-employment background checks in WA state

The answer to this question is complicated. The employer can only ask about convictions, not arrests. If your job involves financial transactions they can ask about misdemeanor convictions which reflect on your honesty (such as petty theft). Usually they are interested only in felony convictions. NOTE: regardless of your criminal record if you do not fully disclose your situation, if asked, on your job application you can be terminated for that alone. A post hire investigation seems a waste of everyone's money because if it turns up negative facts you didn't disclose the employer has just wasted a great deal of money training you.