西雅图市议会要求西雅图公用事业公司（SPU）对西雅图批发和直接服务区到2020年的保护机会的成本、数量和可靠性进行严格分析。水资源保护潜力评估（CPA）已经完成，使用的标准是，任何确定和分析的措施都不会导致客户失去服务或满意度。没有考虑采取缺水行动，例如禁止灌溉，这会减少客户服务。CPA发现，在未来20年内，在不降低客户用水能力和对供水服务满意度的情况下，可以实现大量节水，每天可节约3100万加仑（mgd），或在旺季节约16%的用水。 这些节约的成本与新的旺季供水的当前边际成本相当。

The Seattle City Council asked Seattle Public Utilities (SPU) to provide a rigorous analysis of the cost, volume, and reliability of conservation opportunities available within Seattle's wholesale and direct service areas through 2020. The Water Conservation Potential Assessment (CPA) was completed, using the criterion that no measure identified and analyzed will result in a loss of service or satisfaction for the customer. Water shortage actions such as irrigaiton bans that would reduce customer service were not considered. The CPA found that substantial water savings, up to 31 million gallons per day (mgd) or 16% of water use in the peak season, can be achieved over the next 20 years with no reduction in customers' ability to use water nor in their satisfaction with water services. The cost of these savings is comparable to the current marginal cost of new peak season water supply.