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WATER SUPPLIES
Contributed by Dr.E.Windle Taylor, C.B.E., M.A., M.D., D.P.H., F.C.Path
Director of Water Examination, Metropolitan Water Board
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 population supplied direct according to the Registrar General's estimates at 30th
June, 1968, was 236,900.
No houses were permanently supplied by standpipe.
No fluoride was added, and where 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 Group - Ashford Common, Kempton Park,
Hanworth Road and Barn Elms)
Lea Bridge Works
Ferry Lane Works
Chingford MiII
Coppermills Works (Summer only)
No new sources of supply were instituted and there were no changes in the general
scheme of supply.
The number of samples collected and the bacteriological and chemical analyses of the
supply from the above sources after treatment are shown on pages
On account of their hardness content and alkaline reaction the Board's river and well
water supplies are not considered to be 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.
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. The results of the tests are shown in the following
table:-
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