London's Pulse: Medical Officer of Health reports 1848-1972
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Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
Harrow 1948
[Report of the Medical Officer of Health for Harrow]
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28
SANITARY CIRCUMSTANCES OF THE AREA
WATER.
Apart from a small part of the south-west portion of the district
served by the Rickmansworth & Uxbridge Valley Water Company
(supplied from stations at Ickenham, West Drayton and Mill End) the
area is supplied with water by the Colne Valley Water Company. The
water originates in gathering grounds in the Chilterns, the area of supply
being some 80 square miles. It is pumped at a number of stations from
wells about 200 feet deep in the chalk, the main pumping stations being
at Aldenham Road, Bushey, Berry Grove, near Aldenham, and Eastbury
Road, between Bushey and Rickmansworth. The water is softened,
part by Clark's lime process, part by the method of base-exchange, and
is then chlorinated. The service reservoirs are at Windmill Lane,
Bushey Heath. A boosting station at Grove Hill Road ensures adequate
pressure on Harrow Hill.
The purity of the water is ensured by the supervision carried out by
a staff of chemists and bacteriologists.
Water undertakers who derive their powers by special statutory
enactments are required to ensure the water supplied by them to consumers
is at all times wholesome. Section 111 of the Public Health Act,
1936, imposes a duty on every local authority to take from time to time
such steps as may be necessary for ascertaining the sufficiency and wholesomeness
of the supplies within the district. As a routine practice, then,
samples are submitted quarterly for both chemical and bacteriological
analysis.
Below is set out one of these analyses of a sample taken which is typical of all those which have been submitted:—
"Appearance: bright with a very slight flocculent deposit consisting of chalk particles.
| Colour | Nil | Iron | 0.03 |
| Odour | Nil | Turbidity | less than 5 |
| pH | 7.3 | Taste | Nil |
| Electric conductivity | 600 | Free carbon-dioxide | 14 |
| Chlorine | 50 | Total solids | 400 |
| Hardness total | 215; | Alkalinity | 205 |
| temporary 205; permanent | 10 | N in nitrites | under 0.01 |
| N in nitrates | 5.0 | Oxygen absorbed | 0.20 |
| Free ammonia | 0.014 | Residual chlorine | absent |
| Albuminoid ammonia | 0.014 | Other metals | absent |
"This sample is practically clear and bright in appearance since it
carries only a trace of matter in suspension. The water is neutral in
reaction, hard in character, but not unduly so, contains no excess of
salinity or mineral constituents in solution, and it is free from metals,
apart from a negligible trace of iron. It is of a high standard of organic
quality."
In addition, copies are received regularly from the analyst of the
Colne Valley Water Company of the results of analyses carried out on
samples of water collected from houses throughout the district. These
have been uniformly good.