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69
WATER SUPPLY
The Metropolitan Water Board is responsible for supplying water to this
area and the Director of Water Examination has kindly supplied the following
information:-
The supply was satisfactory both as to quality and quantity throughout
1968.
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 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.
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 estimate at 30th June, 1968, was 243,180.
No houses were permanently supplied by standpipe.
No artificial fluoride was added, and where the fluoride content is
indicated in the analyses it represents the naturally occurring fluoride in
the water.
The supply was derived from the following works and pumping stations:-
River Thames (Northern and Southern groups)
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 source after treatment are shown on
page 70.
On account of their hardness content and alkaline reaction the
Board's river and well water supplies are not considered to be plumbosolvent.
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.
Special tests for lead have been carried out during 1968 on 100 premises
where a lead supply pipe is installed. The premises were chosen to give an
even distribution of samples throughout the whole of the Board's area.
Two samples were collected from each premises; one was the first running
of water standing in the lead pipe overnight and the other was a sample of
water after running the tap for a few minutes. The results are set out in
the accompanying table:-