Reduced irrigation water available for public open space (POS) due to groundwater depletion is an emerging problem in many urban areas. Local governments in Perth face mounting pressure to maintain high quality POS while being driven to use less groundwater for irrigation. Options are to either obtain irrigation water from alternative sources or reduce water use. A third  option is to improve water use efficiency through applying different water savings technologies. Understanding the cost of the options available to maintain POS with less water can help local governments implement water savings techniques that are more cost-effective than alternative sources.