Water conservation initiatives seldom quantify the volume of water that is at stake in lawn watering. In many communities, including those in South Florida, outdoor water use, which includes lawn irrigation, is not metered separately from indoor water use and is indistinguishable from indoor water usage. A large number of residents use self supply non-potable wells for lawn irrigation that are not regulated by the South Florida Water Management District. The result is that residential lawn water use is difficult to account for and quantify. This thesis project addressed these difficulties by combining semi-structured interviews, daily watering observations and irrigation system audits to ascertain how much public supply water and self supply (well) water was being used for residential lawn irrigation. The study also examined lawn watering practices and how factors such as: precipitation, the minimum plant needs of St. Augustinegrass, and how local watering restrictions influenced watering behavior.