[en] The municipal and industrial use of groundwater at the Los Alamos National Laboratory and Los Alamos County was about 1.5 billion gallons during 1986. From a total of 19 wells that range in age from 5 to 41 years, the water was pumped from 3 well fields. The life expectancy of a well in the area ranges from 30 to 50 years, dependent on the well construction and rate of corrosion of the casing and screen. Twelve of the wells are more than 30-years old and, of these, four cannot be used for production, three because of well damage and one because the quality of water is not suitable for use. Eight of the twelve oldest wells are likely to be unsuitable for use in the next 10 years because of well deterioration and failure. The remaining 7 wells include 2 that are likely to fail in the next 20 years. Five of the younger wells in the Pajarito well field are in good condition and should serve for another two or three decades. The program of maintenance and rehabilitation of pumps and wells has extended production capabilities for short periods of time. Pumps may be effectively repaired or replaced; however, rehabilitation of the well is only a short-term correction to increase the yield before it starts to decline again. The two main factors that prevent successful well rehabilitation are: (1) chemicals precipitated in the gravel pack and screen restrict or reduce the entrance of water to the well, which reduces the yield of the well, and (2) the screen and casing become corroded to a point of losing structural strength and subsequent failure allows the gravel pack and formation sand to enter the well. Both factors are due to long-term use and result in extensive damage to the pump and reduce the depth of the well, which in turn causes the yield to decline. Once such well damage occurs, rehabilitation is unlikely to be successful and the ultimate result is loss of the well. Two wells were lost in 1987 because of such damage. 29 refs., 15 figs., 15 tabs