ial of pipes. House drains should be made either of glazed
stoneware pipes or fireclay pipes with cement joints, or preferably of
cast iron pipes jointed with carefully-made lead joints, or with
turned joints and bored sockets. I say preferably of cast iron. In New
York the iron soilpipe, with joints made with lead, is now required by
the municipal regulations. It is a stronger pipe than a rainwater
pipe. The latter will often be found to have holes. A lead joint
cannot be made properly in a weak pipe, therefore the lead joint is to
some extent a guarantee of soundness. Lead pipes will be eaten away by
water containing free oxygen without carbonic acid, therefore pure
rainwater injures lead pipes. An excess of carbonic acid in water will
also eat away lead. You will find that in many cases pinholes appear
in a soilpipe, and when inside a house that allows sewer gas to pass
into the house. Moreover, lead is a soft material; it is subject to
indentations, to injury from nails, to sagging. A cast-iron pipe, when
coated with sewage matter, does not appear to be subject to decay; and
if of sufficient substance it is not liable to injury. When once well
fixed, it has no tendency to move. I would, therefore, advocate cast
iron in lieu of lead soilpipes. In fixing the soilpipe which is to
receive a water-closet, the trap should form part of the fixed pipe;
so that if there is any sinking the down pipe will not sink away from
the trap. It is, however, not sufficient to provide good material.
There is nothing which is more important in a sanitary point of view
than good workmanship in house drainage. In this matter, it is on
details that all depends. Just consider; the drain pipes under the
best conditions of aeration contain elements of danger, and those
pipes are composed of a number of parts, at the point of junction of
any one of which the poison may escape into the house. You thus
perceive how necessary it is first to reduce the poison to a minimum
by cutting off the sewer gas which might otherwise pass from the
street sewer to the house drain, and in the next place being most
careful in the workmanship of every part of your house drains and
soilpipes. Reduce your danger where you can by putting your pipes
outside. But you cannot always do that--for instance, at New York and
in Canada they would freeze.

All drain pipes should be proved to be watertight by plugging up the
lower end of the drain pipe and filling it with water