According to the Fire Marshall the City code states “house numbers should be visible at all times from the street.” Take a look at your house from the street. Can you see your house numbers? Perhaps shrubbery is overgrown or your house numbers are faded. If your brass house numbers are faded and not restorable please replace them.
Whittier requires that all exterior changes be “In-kind repairs/upgrades which maintain the original appearance of the structure”. In-kind replacement of house numbers would be 4” brass numbers only. Local stores such as Lowe’s and Home Depot have them. Consider solid brass over brass plated since these tend to stay brighter a lot longer. They cost more but they last longer.