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.