This report presents June 1987 water-quality data, principally dissolved chloride and dissolved nitrite plus nitrate (as nitrogen), for water samples from 45 wells in the Murtaugh Lake area, south-central Idaho. Chloride concentrations ranged from 23 to 320 milligrams per liter; the median concentration was 70 milligrams per liter. Nitrogen concentrations ranged from less than 0.1 to 11.0 milligrams per liter; the median concentration was 3.7 milligrams per liter. Chloride concentrations in 6 samples and nitrogen concentrations in 3 samples equaled or exceeded the U.S. Environmental Protection Agency public drinking-water limits of 250 and 10 milligrams per liter, respectively.