Q. I desire a little information in regard to a method (proposed to me by my plumber) of connecting the waste from wash-basin and bathtub with that from water-closet before piercing the main 4-inch iron soil-pipe. He proposes to trap both basin and bath-tub separately (the traps being ventilated to the roof) and to unite these waste-pipes below the traps and carry the waste into the upper part {above the water-line) of a large trap situated just below the trap of a Jennings all-earthen closet. Both the earthen trap of the Jennings closet and this large lead trap are to be ventilated to the roof. In this case you will observe that all three wastes are separately trapped and ventilated, and that the united waste passes into another trap, also ventilated, before discharging into the main soil-pipe. Is this arrangement good from a sanitary point of view?

Another question: The ventilating-pipes from these different traps just referred to he proposes to unite at convenient points above the level of the traps, and to carry the whole in one into a 2-inch ventila-ting-pipe and thus to the roof. Is this arrangement as good as to pierce the 2-inch pipe in four different places for the separate ventilating-pipes, and thus ventilate to the roof?

A. In answer to the first query, we should say that, assuming that each fixture is separately trapped and properly ventilated, the advantage of the large trap just below the water-closet trap is not apparent. On the other hand, we consider such a trap as objectionable, for the reason that it retards somewhat the flow of waste matter without securing any adequate advantage as an offset for its being there. From the question as it stands, and in the absence of a sectional drawing, we should consider the several fixtures, trapped and ventilated as described, as amply protected, assuming, of course, that the house-drains are otherwise all right. A needless trap is an injury rather than a benefit.

Secondly - As we understand your last question, we should say that the choice of methods was simply a matter of convenience and economy in the use of pipe, provided that the 2-inch pipe was used solely for ventilation and received no drainage.