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additional By-laws or additional provisions for special circumstances
requiring iron drainage to be constructed instead of earthenware, and the
conditions of such construction.
The attention of your Committee should also he directed to the particular
By-laws referring to sub-soil drainage. There is no provision against the
reflux of sewage into a sub-soil drain, either from a choked sewer, a blocked
manhole, or a stopped drain. Some such provision as this is required : -
"He shall cause such traps to be provided with a suitable ball or valve
"which will effectually prevent any reflux of sewage into the sub-soil drain
"from the sewer or drain carrying sewage into which the sub-soil drain
"discharges; and he shall provide 011 the sub-soil drain side of the trap a
"manhole, and along the bottom of this manhole a half channel pipe, and
"over the top of this manhole a grating, so that any reflux of sewage into
"the sub-soil drain can be readily seen."
I beg to recommend that a communication be made to the County Council
accordingly.
Another point to which I would beg to call attention is that By-law 3 (first
paragraph) of the Drainage By-laws is constantly being interpreted to mean
that a rain-water pipe must be taken directly downwards to discharge over or
into a trapped gully, and often inside a house. For years I have advised
architects, builders, and others to "keep the rain or surface waters as high as
possible as long as possible," in order to retain as much head of water or
gravitation as possible, so as to enable the rain water to be carried from roof to
roof and surface to surface to any necessary distance to the lowest open area
where a gully may be placed.
I beg to recommend that in order to facilitate this, to the end of the first
paragraph of By-law 3 of the Drainage By-laws, which regulates the discharge
of rain-water pipes, the following words be added:—
"Or over a channel, or into a hopper head, or on to a roof, or other
"impervious properly levelled and drained surface."
On the 12th September, 1906, I reported to your Public Health Committee
upon the particular By-laws regulating the size of soil pipes and vent pipes.
This report was considered and approved by the Borough Council on the
19th September, i906, and forwarded to the County Council. The substance
of this report was condensed and reproduced in the Annual Report for 190G
as follows:—
"Drainage By-laws, Regulating the Size of Pipes.—Builders still
"continue to complain that they are allowed to put up a 3½-in. soil pipe
"and a 3½-in. vent pipe to ventilate a 4-in. drain, but if they ventilate a
"4-in. drain, not having a soil pipe but a branch W.C. drain on the same
"level, they are compelled to make the branch 4-in. diameter, and the
" vent pipe 4-in. diameter.
"In other words, if the vertical vent pipe is the continuation of a
"4-in. horizontal drain, it must be 4-in. in diameter, but if to this vertical
"vent pipe a W.C. is connected it becomes a soil pipe, and may, together
"with the soil pipe, be reduced to 3½-in. in diameter.