There is no official account precisely defining the length of the
London sewerage; but the information acquired on the subject leaves no
doubt as to the accuracy of the following facts.
About 900 miles of sewers of the metropolis may be said to have been
surveyed; and it is known that from 100 to 150 miles more constitute a
portion of the metropolitan sewerage; this, too, independently of that
of the City, which is 50 miles. Altogether I am assured that the sewers
of the urban part of London, included within the 58 square miles before
mentioned, measure 1100 miles.
The classes of sewers comprised in this long extent are pretty equally
apportioned, each a third, or 366 miles, of the first, second, and
third classes respectively. Of this extent about 200 miles are
still, in the year 1852, _open_ sewers!--to say nothing of the great
open sewer, the Thames. The open sewers are found principally in
the Surrey districts, in Brixton, Lewisham, Tooting, and places at
the like distance from the more central parts of the Commissioners’
jurisdiction. These open sewers, however, are disappearing, and it is
intended that in time no such places shall exist; as it is, some miles
of them are inclosed yearly. The open sewers in what may be considered
more of the heart of the metropolis are a portion of the Fleet-ditch in
Clerkenwell, and places in Lambeth and Bermondsey, or about 20 miles in
the interior to 180 miles in the exterior portion of the capital. These
are national disgraces.
The 1100 miles above-mentioned, however, include only the sewers,
comprising neither the house nor gully-drains. According to the present
laws, all newly-built houses must be drained into the sewers; and in
1850 there were 5000 applications from the western districts alone to
the Commissioners, for the promotion of the drainage of that number
of old and new houses into the sewers, the old houses having been
previously drained into cesspools.
I am assured, on good authority, that fully one-half of the houses in
the metropolis are at the present time drained into the sewers. In
one street, about a century old, containing in the portion surveyed
for an official purpose, on the two sides of the way, 76 houses, the
number was found to be equally divided--half the drainage being into
sewers and half into cesspools. The number of houses in the metropolis
proper, of 115 square miles area, is 307,722. The majority, as far
as is officially known, are now drained into the public sewers, or
into private or branch sewers communicating with the larger public
receptacles, so that--allowing 200,000 houses to be included in the 58
square miles of the urban sewerage, and admitting that some wretched
dwelling-places are not drained at all--it is reasonable to assume that
at least 100,000 houses within this area are drained into the sewers.
The average length of the house-drains is, I learn from the best
sources, 50 feet per house. The builder of a new house is now required
by law to drain it, at the proprietor’s cost, 100 feet, if necessary,
to a sewer. In some instances, in detached houses, where the owners
object to the cesspool system, a house drain has been carried 230 feet
to a sewer, and sometimes even farther; but in narrow or moderately
wide streets, from 18 to 26 feet across, and in alleys and narrow
places (in case there is sewerage) the house drains may be but from 12
to 20 feet. Both these lengths of drainage are exceptions, and there
is no question that the average length may be put at 50 feet. In some
squares, for example, the sewer runs along the centre, so that the
house-drains here are in excess of the 50 feet average.
The length of the house-drainage of the more central part of London,
assuming 100,000 houses to be drained into the sewers, and each of such
drains to be on the average 50 feet long, is, then, 5,000,000 feet, or
about 2840 miles.
But there are still the street or gully-drains for the surface-water to
be estimated. In the Holborn and Finsbury division alone, the length
of the “main covered sewers” is said to be 83 miles; the length of
“smaller sewers” to carry off the surface-water from the streets 16
miles; the length of drains leading from houses to the main sewers, 264.
Now, if there be 16 miles of gully-drains to 83 miles of main covered
sewers, and the same proportion hold good throughout the 58 square
miles over which the sewers extend, it follows that there would be
about 200 miles of gully-drains to the gross 1100 miles of sewers.
But this is only an approximate result. The length and character of the
gully-drains I find to vary very considerably. If the streets where the
gully-grates are found have no sewer in a line with the thoroughfare,
still the water must be drained off and conveyed to the nearest sewer,
of any class, large or small, and consequently at much greater length
than if there were a sewer running down the street. Neither is the
number of the gully-holes any sure criterion of the measurement of the
gully-drains, for where the intersections are, and consequently the
gully-holes frequent, a number, sometimes amounting to ten, are made to
empty their contents into the same gully-drain. Neither do the returns
of yearly expenditure, presented to Parliament by the Metropolitan
Court of Sewers, supply information. But even if the exact length, and
the exact price paid for the formation of that length, were given,
it would supply but _the year’s_ outlay as regards the additions or
repairs that had been made to the gully-drains, and certainly not
furnish us with the original cost of the whole.
One experienced informant told me--but let me premise that I heard
from all the gentlemen whom I consulted, a statement that they could
only compute by analogy with other facts bearing upon the subject--was
confident, that taking only 1200 miles of public way as gully-drained,
that extent might be considered as the length of the gully-drains
themselves. Even calculating such drains to run from each side of the
public way, which is generally the case, I am told that, considering
the economy of underground space which is now necessary, the length of
1200 miles is as fair an estimate for gully-drainage (apart from other
drainage) as for the length of the streets so gullied.
Hence we have, for the gross extent of the whole sewers and drains of
the metropolis, the following result,--
Miles.
Main covered sewers 1100
House-drains 2840
Gully-drains for surface-water of
streets 1200
----
Total length of the sewers and
drains of the metropolis 5140
The island of Great Britain, I may observe, is, at its extreme
points, 550 miles from north to south, and 290 from east to west. It
would, therefore, appear that the main sewers of the capital are just
double the length of the whole island, from the English Channel to
John-o’-Groats, and nearly three times longer than the greatest width
of the country. But this is the extent of the sewerage alone. The
drainage of London is about equal in length to the diameter of the
earth itself!