These days depend on whether you have an odd or even numbered address, and the time of year.
During Daylight Savings Time: homes with odd numbered addresses or no addresses can water on Wednesday and Saturday. Homes with even numbered addresses can water on Thursday and Sunday.
During Eastern Standard Time: homes with odd numbered addresses or no addresses can only water on Saturdays. Homes with even numbered addresses can only water on Sundays.
In addition to the days of the week that you can water, there are other rules dictating how long you can water, etc. For the complete rules, visit the Watering Restrictions page on the St. Johns River Water Management website.