Both shallow-dug wells and deep-bored wells may be polluted by the entrance of filth, vermin, unclean water at the top and also by seepage of contaminated soil water. These are the results of poor location of wells, generally unclean surroundings, open or loose well curbs, the absence of a well lining, or the presence of a poor well lining. The first step in securing a clean water supply is to remove all sources of possible contamination. Among the worst of these is the open privy vault, the leaching cesspool, and barnyard filth. A well in ordinary pervious soil, located lower than and within 100 feet of any of these, is almost certain to be contaminated. The well itself should be located as high as possible with regard to buildings, stock pens, and chicken yards, and as far away from all sources of contamination as convenience and local surroundings will permit. The final safeguards to a well-water supply are to provide an impervious lining of concrete, cemented bricks, cemented tile, or iron casing, and to provide a water-tight curb, not only to keep out surface wash, animals, and vermin, but to prevent the pump drip and dirt from shoes and bucket from entering the well.
Fig. 18.—Dug well, vitrified tile lining.
Fig. 19.—Bored well.
Fig. 20.—Driven well.
The same precaution with reference to the entrance of filth and polluted water from the surface apply to underground cisterns.
Springs are subject to contamination by surface wash and because animals have access to them. They can be protected by fencing in from animals, walling in the spring to form a covered and water-tight reservoir, and by keeping the surroundings clean. Spring water should be kept under close observation for any signs of surface pollution, especially those springs occurring in limestone regions.
Having secured a clean water supply, the next step is to provide equipment to furnish running water in the kitchen at the turning of a faucet or by merely pumping.