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Section C— Sanitary Circumstances.
Water Supply.
All the properties in the district have a mains supply of water.
The Sutton District Water Company supplies almost the whole of the
area except for some 170 dwellings in the extreme north which are
served by the Metropolitan Water Board.
Daily examinations of the raw and finished waters are made by
the Company's chemist, who is employed full-time. These are supplemented
at intervals by chemical and bacteriological examinations
undertaken for the Company by The Counties Public Health
Laboratory.
A further check on the suitability of the supply is provided by
monthly examinations carried out on a rota by the Public Health
Departments of the districts supplied by the Company. In addition
to softening, the water is treated with chloramine, the process being
arranged so as to leave a trace of residual chlorine in the finished
product. Two routine samples were taken by this Council in accordance
with the rota referred to and were satisfactory. One of these,
which is fairly representative, was reported upon as follows:—
Chemical analysis in parts per 100,000.
Total solid matter in solution (dried at 180° C.) 17.2
Combined chlorine 1.30
Nitric nitrogen 0.42
Nitrous nitrogen 0.004
Ammonia, free and saline 0.0025
Ammonia, albuminoid 0.001
Oxygen absorbed from permanganate in 4 hours at 26.7° C. 0.008
Hardness—by acidimetric titration—
Temporary 10.5
Permanent 3.0
Total 13.5
pH 7.5
Reaction for free chlorine: positive, equivalent to 0.17 part per million.
The water was bright and clear and was normal in colour.
Bacteriological examination.
Action by free chlorine during transit of the sample was prevented
at the time of sampling.
Number of colonies per ml. developing upon agar in 2 days at 37° C. 0
Number of colonies per ml. developing upon agar in 3 days at 22° C. 1
Coli aerogenes organisms absent in 100 ml.
Streptococci do.
B. welchii do.
This water is of high organic purity and its bacteriological condition is excellent.
The water is suitable for the public supply.
The supply is not regarded as being liable to plumbo-solvent
action.
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