Lining of open sanitary well should be extended to a minimum depth of?: (A) 5 feet, (B) 10 feet, (C) 15 feet, (D) 20 feet
Answer is D. Ans. is 'd' i.e.,20 feet the well should be located not less than 15 m (50 feet) from likely sources of contamination. The well should be located at a higher elevation with rspect to a possible source of contamination.