虽然美国人口在增长，但淡水供应却在减少，因此，节约用水和重复利用水资源的需求变得十分必要。节约用水可以通过减少室内和室外使用来实现。水的再利用包括回收废水、灰水，更重要的是城市径流。其中，废水和灰水在这个国家已经循环使用了一段时间，主要用于灌溉。然而，城市径流资源丰富，处理成本比废水低，尚未得到利用。本文概述了室内和室外使用的保护措施以及相关的节水措施。 此外，简要回顾了废水和灰水的再利用。本文讨论了城市雨水径流的再利用，这是一种被实践工程师忽视的重要资源。此外，还对屋顶径流的再利用进行了更详细的讨论。屋顶径流相当纯净，适用于所有户外用途。我们估计，典型郊区半英亩地块开发的一平方英里平均年径流超过1.04亿加仑（152000 m3/sqkm）。我们还估计，平均年人均屋顶径流为19000升（5000加仑）。即使收集一部分屋顶雨水，也能为我们提供大量的水源。 本文提出了全国各地收集屋顶径流的雨水池的建议尺寸。包括11个参考文献和表格。

While the U.S. population is growing, the freshwater supplies are diminishing and therefore, the need to conserve water and reusing it is becoming a necessity. Conservation of water can be achieved through reduction of both indoor and outdoor uses. The reuse of water includes recycling wastewater, gray water and more importantly, the urban runoff. Among these, the wastewater and gray water has been recycled in this country for sometime, mostly for irrigation uses. However, the urban runoff which is plentiful and less costly to treat than wastewater is yet to be used. This paper presents an overview of conservation measures in indoor and outdoor uses and associated water savings. Also, briefly reviewed are the reuse of wastewater and gray water. Discussed in the paper are the reuse of urban stormwater runoff, a significant resource which is neglected by practicing engineers. The reuse of roof runoff which is fairly pure and suitable for all outdoor uses is also discussed, in more detail. We estimate that the average annual runoff from a square mile of a typical suburban, one-half acre lots development is over 104 million gallons a year (152,000 m3/ sqkm). We also estimate the average annual per capita roof runoff is 19000 L (5000 gallons). Even collecting a portion of the roof rain provides us with a significant supply of water. Presented in the paper are suggested sizes of rain tanks for the collection of roof runoff in various parts of the country. Includes 11 references, tables.