<prompt> Minimum depth for the lining of a sanitary well is?10 feet20 feet35 feet50 feet  <response>: The lining of a sanitary well should go down at least 20 feet to ensure that water enters from the bottom and not from the sides of the well. The lining should extend upwards for about 2-3 feet above the ground. Ref: Parks Textbook of Preventive and Social Medicine, 20th edition, p620 