I have an oversized corner lot in Duval - my system has seven zones and if I water twice per week my useage generally runs around 17,000 gallons. During periods when we've watered every day (ex: new landscaping installed) my water useage has been as high as 22,000 gallons
. And when we water once per week my useage is around 8,000 gallons
.
Keep in mind that your useage not only consists of how many days you run your irrigation system but also is impacted by how many zones you have and how long each zone runs.