The minimum wage ordinance takes effect April 1; it will gradually increase the minimum wage in Seattle to $15 (and index it to inflation) depending on the size of the employer and whether the employee receives tips or medical benefits. All employers will have to pay the same minimum wage by 2025. Below is a chart from the city showing how this will work.
Under the proposed rules, employers must pay employees who are under 16 an hourly rate that is at least 85 percent of the new city minimum wage. The rules specify that service charges are not tips. Additionally, if an employee is jointly employed (e.g. with a staffing agency and another company), the amount he is paid depends on the size of the larger employer.
Here is our recent report on the minimum wage.