The average custodian salary at Modesto was $17,119 , which is 76 percent lower than the average salary for this job in California, and 76 percent lower than the national average for this job . Custodian salaries at Modesto typically range from $11,518 to $22,720 (25th to 75th percentile). The highest reported custodian salary was $22,719. There are 2 employees at Modesto with the job title custodian.