Office Assistant Senior salary at Contra Costa Water District

The average office assistant senior salary at Contra Costa Water District was $134,015 , which is 84 percent higher than the average salary for this job in California, and 274 percent higher than the national average for this job . Office Assistant Senior salaries at Contra Costa Water District typically range from $132,170 to $138,704 (25th to 75th percentile). The highest reported office assistant senior salary was $147,628. There are 12 employees at Contra Costa Water District with the job title office assistant senior.