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31
Water supply
I am indebted to the Director of Water Examination and the Clerk
of the Metropolitan Water Board for the information on which the
following report on Lewisham's water supply is based.
The water supply to Lewisham is divided into three zones; the
low zone is supplied from Deptford well and by Thames-derived filtered
water; the Eltham zone is supplied from Wilmington, Darenth and
Bexley wells and should the occasion arise, with a small proportion
from the low zone; the Bromley zone to the south of the Borough is
supplied from Shortlands well and again on occasions with additional
Thames-derived filtered water.
River Thames water is abstracted at the Board's intakes at Walton
and Laleham and is stored in the Queen Mary, Island Barn and Walton
reservoirs. The water is filtered at Hampton, Surbiton and Walton
Works and is chlorinated after filtration. In the case of Hampton, a
contact tank has been built where the chlorine has time to exert its full
effect before the water is pumped into supply; consequently the water
in the distribution system is for the greater part of the year free or
almost free from residual chlorine. A similar contact tank is in an
advanced stage of construction at Walton works and plans are being
prepared for a contact tank at Surbiton works.
All the well water is chlorinated and, in addition, contact tanks
are provided at Deptford, Wilmington and Bexley wells; any residual
chlorine is wholly or almost completely removed before the water leaves
the works.
Bacteriological analyses are made at least five times a week and
in the case of the river-derived supplies, the water is analysed at all
stages of purification. All new and repaired mains are chlorinated before
being restored to use and samples are collected for analysis to establish
that the quality of the water is up to the standard normally supplied.
None of the supplies is plumbo-solvent.
All houses in Lewisham are supplied directly and not by means of
standpipes.
Appended are the average results of the chemical and bacteriological
analyses of the various supplies as fowarded by the Metropolitan Water
Board.