Significant development of ground water in the El Paso area started in the early 1900's; pumping gradually increased to the early 1950's and has since accelerated commensurate with the area's rapid population growth. In 1980, withdrawals of ground water for municipal, industrial, and military supplies totaled 164,354 acre-feet (203 cubic hectometers) within the El Paso, Fort Bliss, and Ciudad Juarez, Mexico metropolitan area, and adjacent areas in Texas and New Mexico. Most of the water, 132,652 acre-feet (164 cubic hectometers), was pumped from the Hueco bolson, the principal aquifer. The Mesilla bolson and Rio Grande alluvium in the lower Mesilla Valley supplied 27,461 and 4,241 acre-feet (34 and 5 cubic hectometers) respectively.

The cumulative 1906 through 1980 withdrawals of ground water from the Hueco bolson metro area total 3.0 million acre-feet (3.7 cubic kilometers)-about 2.2 million acre-feet (2.7 cubic kilometers) has been pumped in the United States and 0.8 million acre-feet (1.0 cubic kilometers) in the Republic of Mexico. These withdrawals have caused water levels to decline about 130 feet (40 meters) in the downtown sections of El Paso and Ciudad Juarez. In January 1980 the theoretically recoverable volume of freshwater in storage within the Texas part of the Hueco bolson metro area was estimated at 10.0 million acre-feet (12 cubic kilometers). Dissolved-solids concentrations in recent samples from Hueco bolson wells averaged 642 milligrams per liter in the Texas part of the metropolitan area and 736 milligrams per liter in Ciudad Juarez. Concentrations are increasing at an average-annual rate of about 10 milligrams per liter in Texas and 30 milligrams per liter in Juarez.

Ground water in the lower Mesilla Valley is pumped for municipal and industrial supply and also for supplemental crop irrigation during years of inadequate surface-water supply in the Rio Grande. The 1979-80 withdrawals in the valley averaged about 31,000 acre-feet per year (38 cubic hectometers). Most of the water, about 21,000 to 22,000 acre-feet per year (26 to 27 cubic hectometers), was pumped from shallow, medium depth, and deep wells in the Canutillo field. Dissolved-solids concentrations from recent samples from Canutillo wells ranged from 252 to 1,854 milligrams per liter.

Flow in the Rio Grande is diverted for crop irrigation in the United States and the Republic of Mexico, and for limited municipal supply in El Paso. The flow is regulated by releases from reservoirs in New Mexico and varies widely in both quantity and quality (dissolved-solids concentrations). During 1943-80, the flow at El Paso ranged from 57,481 acre-feet (71 cubic hectometers) in 1956 to 631,800 acre-feet (779 cubic hectometers) in 1943 and averaged about 317,000 acre-feet per year (391 cubic hectometers).