At no time were all reservoirs overflowing simultaneously. This is the first year that this has happened since the Tai Lam Chung reservoir was commissioned in 1957. This emphasizes the fact that until substantially increased resources become available the ratio of demand to storage is now so high that satisfactory hours of supply cannot be given except under exceptionally favourable conditions, and even in the middle of the wet season extreme care is necessary to ensure that adequate water is available for the winter.
Consumption
10.09. The total quantity of water consumed in the Urban Areas was 25,240 million gallons, and in the New Territories 861 million gallons. These are decreases on the previous year of 3,658 and 249 million gallons respectively. The total number of hours of supply was decreased by 49% to 2,371 hours.
Distribution
10.10. Although improvements to the distribution system limited the number of complaints, the short hours of supply made distribution conditions far from easy.
Water Analysis
10.11. The standard of purity aimed at is complete absence of coli-form organisms in 100 cc. of treated water. This is as high as anywhere in the world, and is systematically checked by samples taken by Waterworks personnel and tested by the Government Pathologist.
10.12. It was found that only 4.1% of 346 samples taken from service reservoirs, and 9.0% of 1,350 taken from consumers' taps were below the requisite standard. Where sub-standard samples were recorded from service reservoirs, the chlorine dosage was temporarily increased and subsequent samples proved satisfactory. Of the unsatisfactory tap samples, 1 was attributed to a fractured sub-main, 1 was due to a leaking main, and 100 to defective inside services; 16 were under investigation at the close of the year, while the cause of 3 could not be traced and were probably due to improper sampling. After the defects had been rectified, subsequent samples proved satisfactory in every case.
In addition, all chemical samples taken proved satisfactory.
Pumping
10.13. The following table shows the quantities of raw and filtered water pumped in comparison with those for the previous years:
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