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Number of Samples Number of Samples
giving results above 0 per giving plate counts above
Source of Supply Number of Samples 1 00 mis. 0 Cols/ml after 24 hours
Coliform Bact. Coli. at 37°c.
Count (Type 1)
1. Deep wells within the
City area 42 1 — 15
2. Metropolitan Water
Board 119 1 1 88
3. Swimming Pools within
the City 95 — — 19
TOTAL 256 2 1 122
Three samples were unsatisfactory. In each case an investigation was carried out immediately
and appropriate measures taken to eliminate the source of contamination. Subsequent samples
taken from the same premises proved to be satisfactory.
The Director of Water Examination of the Metropolitan Water Board has supplied the following
Report:-
"1.(a) The supply was satisfactory both as to (i) quality, and (ii) quantity throughout 1972.
(b) All new and repaired mains are disinfected with chlorine; after a predetermined period
of contact the pipes are flushed out and refilled; samples of water are then collected
from these treated mains; and the mains are returned to service only after the analytical
results are found to be satisfactory.
The quality control from these laboratories is carried out by means of daily sampling
from sources of supply, from the treatment works or well stations, from the distribution
system, and through to the consumer. Any sign of contamination or any other abnormality
is immediately investigated.
(c) (i) The Board has no record of the number of structurally separate dwellings supplied
in your area, but the population supplied direct according to the Registrar-General's
estimates at 30th June, 1972, was 4,449.
(ii) No houses were permanently supplied by stand-pipe.
(d) No artificial fluoride is being added, and where the fluoride content is indicated in the
analyses it represents the naturally occurring fluoride in the water.
2.(a) The supply was derived from the following works and pumping stations:-
River Thames-derived water from Thames Valley grouped stations. New River-derived water
from Stoke Newington works.
No new sources of supply were instituted and there were no changes to the general
scheme of supply in your area.
The number of samples collected and the bacteriological and chemical analyses of the
supply from the above sources after treatment are shown on the attached sheets.
(b) On account of their hardness content and alkaline reaction the Board's river and well
water supplies are shown to be not plumbo-solvent. It should, however, be appreciated
that all types of water pick up varying amounts of metal from the material of water piping
particularly when it is newly installed; this applies to copper, zinc, iron and also to lead."
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