The subject of country plumbing differs in many respects from the plumbing of cities and towns. The difference arises principally because of the fact that usually the plumbing system installed in the country cannot enter a system of public sewers, and a water supply cannot be secured from any public system of supply. These conditions make it necessary to study each individual plumbing system, and to provide for it as conditions require.
Another feature that also influences the installation of the plumbing system, is the absence of any regulation or inspection of plumbing work. As a consequence, many houses in the country, of ordinary style, are provided with an unvented plumbing system. This, however, in many cases need not be a serious matter, as on small systems special provision may often be made for making the work as safe as is possible to make it when the traps are not vented.
Plate XLVII. Country Plumbing - Water Supply
Plate 47 shows such a plumbing system.
In many cases one stack serves all plumbing fixtures of the house, including usually the three bath-room fixtures, kitchen sink, and, possibly, laundry tubs. The use of S-traps on such work is poor practice, as this form of trap is easily siphoned, unless provided with a vent. The use of drum traps and approved forms of non-siphonable traps is much better practice. As far as possible, long, horizontal runs of lead waste pipe should be avoided in an unvented plumbing system, as siphonage often results from the backing up of waste in these long runs. The connections from bath-room fixtures into the stack can usually be arranged as shown in Plate 47, with the lavatory waste entering above the water-closet connection. If the lavatory connection is below the closet connection, the liability of siphonage of the lavatory trap will be greater, owing to the passage of a heavy volume of waste from the water closet past the lavatory waste opening.
The passage of the stack through the roof is a great safeguard for any system of plumbing, especially in the case of an unvented system. When the country plumbing system empties into a cesspool or septic tank, a vent should be run from such receptacle. The septic tank or cesspool, stands in the same relation to the country plumbing system that the public sewer system does to the city plumbing system.
If the cesspool or sewer is not vented, gases will generate and produce a pressure that will force the seal of the main trap.
The soil vent or roof connection relieves this pressure, which is a duty of much importance, for if not thus relieved, the fixture traps will also be forced, and poisonous gases from the cesspool thus find entrance into the house. The use or non-use of the main trap does not appear to be a matter of so much importance in connection with the country plumbing system as with the city system. One reason for this is that in the country districts there is no danger of contaminating the surrounding air by venting the cesspool, whereas in the city the venting of the sewer through the soil vents of a building only a few stories in height may throw foul odors and gases into the windows of a high building next to it.
There is one reason why the main trap is of much value to many country systems. There being no regulation by ordinance, or inspection of plumbing, much poor work is installed that remains undiscovered, which a test would quickly reveal; and, moreover, standard soil pipe is generally used, which is easily split in handling, and which has more defects than extra-heavy pipe. Consequently, sewer gas would have a much greater opportunity to find its way through defective pipe and joints than in work of a higher grade, and the main trap will prevent much of this trouble, by preventing the entrance into the plumbing system of the house, of gases from the cesspool.
The subjects of cesspools, sewage siphons, septic tanks, etc., are considered more thoroughly under the two plates following.