Nonprice conservation programs appear to be effective if the water utility achieves a critical mass of programs. For Los Angeles, San Diego and Denver, the number of nonprice programs has had the desired effect. For cities with fewer programs or relatively new experience with conservation programs, the nonprice programs had no effect on demand. Conservation programs work independently of a drought environment, such as California had in the late1980s and early 1990s, and continue to work after the drought conditions have ceased. Conservation programs may be ultimately necessary simply to counteract an exogenous long-term increase in residential uses.
Climate affects residential use in predictable ways.
Water use is strongly correlated with average monthly temperature and seasonal variation in temperature. Precipitation was consistently insignificant in all models. All cities in this analysis are semi-arid to arid in climate, and thus the ratio of evapotranspiration to precipitation is much greater. Landscape watering is necessary if one wants to maintain traditional residential lawns and trees. Random and infrequent rains don't change residential watering patterns to a significant degree.