Wells are exposed to contamination in two ways. The surface water from
rain, house slops, and barnyard drainage may find its way into the well at
or near the surface of the ground. Or the ground-water stream supplying
the well with water may in its subterranean movements encounter cesspools
or seepings from cesspools, and carry with it soluble and suspended
particles, some of which may enter the well. There can be no doubt that
a large percentage of the wells are exposed to contamination with refuse
matter in the manner described; and it now remains to gauge the danger
to health and life which may be carried in the contaminating substance.
The danger of typhoid-fever bacteria entering the water has already been
mentioned. These may be washed in from the surface or they may pass from
cesspools near by through fissures in the ground, passages dug by rats,
etc. Whether such bacteria can pass through the pores of a compact,
unbroken soil from a cesspool to a well near it is a matter not fully
settled. Since, however, the actual condition of the deeper layers of the
soil between cesspool and well can not be known, it becomes imperative
to prevent all pollution of the ground-water current supplying wells by
either abolishing the cesspools or else placing them at a considerable
distance from all sources of water.
Beside typhoid-fever bacteria, those organisms which cause digestive
disturbances, and severer troubles, such as diarrhea, dysentery, and
possibly other unknown diseases, may be carried into well water. During
cholera epidemics, polluted wells might form centers of infection. Eggs of
animal parasites may be washed in from the surface. Again, the barnyard
manure, representing the mixed excrement of various animals, may under
certain conditions be bearers of disease germs, and such excrement
should, under no conditions, be looked upon as entirely harmless to human
beings.[2]
[2] It is probable that the filth which gets into cow's milk and which
appears to be mainly excrement of cows is largely responsible for the
severe summer diseases of infants fed on cow's milk.
Besides the protection of the ground-water near the well from pollution
emanating from cesspools, etc., the surface of the ground about the well
should be kept free from manure, slops, and other waste water; hence
the well should not be dug under or close by the house,[3] nor should
it be located in the barnyard, where the ground is usually saturated
with manure. It should be surrounded by turf, and not by richly manured,
cultivated, or irrigated soil. The ground immediately around it should
slope gently away from it and be paved if possible. The waste water from
the well should not be allowed to soak into the ground, but should be
collected in water-tight receptacles or else conducted at least 25 feet
away in open or closed channels which are water-tight.
[3] The water may be carried into the kitchen by running the pipe from the
well, horizontally, under ground.