Where farms have water under pressure an open or leaching cesspool is a common method of disposing of the sewage. Ordinary cesspools are circular excavations in the ground, lined with stone or brick laid without mortar. They vary from 5 to 10 feet in diameter and from 7 to 12 feet in depth. Sometimes the top is arched and capped at the ground surf ace by a cover of wood, stone, or cast iron. At other times the walls are carried straight up and boards or planks are laid, across for a cover, and the entire structure is hidden with a hedge or shrubbery. [Illustration: Fig. 18.--How to waste kitchen-sink drainage. _A_, Sink; _B_, waste pipe; _C_, trap; _D_, clean-out; _E_, box filled with hay, straw, sawdust, excelsior, coke, or other insulating material; _F_, 4-inch vitrified sewer-pipe, hubs uphill, and joints made water tight for at least 100 feet downhill from a well; _G_, 4-inch vitrified sewer pipe, hubs downhill, joints slightly open, laid in an 18-inch bed of coarse sand, gravel, stone, broken brick, slag, cinders, or coke; strip of tarred paper on burlap or a thin layer of hay, straw, cornstalks, brush, or sods, grass side down; _I_, 12 inches of natural soil; _J_, stone-filled pit. As here illustrated, water is drawn by a pitcher or kitchen pump (_K_) through a 1-1/4 or 1-1/2 inch galvanized-iron suction pipe (_L_) from a cistern (_M_). The suction pipe should be laid below frost and on a smooth upward grade from cistern to pump and be provided with a foot valve (_N_) to keep the pump primed. If a foot valve is used, pump and pipe must be safe from frost or other means than tripping the pump be provided for draining the system.] Except under the most favorable conditions the construction and use of a cesspool can not be condemned too strongly. They are only permissible where no other arrangement is possible. Leaching cesspools especially are open to these serious objections: 1. Unless located in porous soil, stagnation is likely to occur, and failure of the liquid to seep away may result in overflow on the surface of the ground and the creation of a nuisance and a menace. 2. They retain a mass of filth in a decomposing condition deep in the ground where it is but slightly affected by the bacteria and air of the soil. In seeping through the ground it may be strained, but there can be no assurance that the foul liquid with little improvement in its condition may not pass into the ground water and pollute wells and springs situated long distances away in the direction of underground flow. For the purpose of avoiding soil and ground-water pollution cesspools have been made of water-tight construction and the contents removed by bailing or pumping. Upon the farm, however, this type of construction has little to recommend it, for the reason that facilities for removing and disposing of the contents in a clean manner are lacking.