The average consumption of filtered water per head per day for all purposes was about 25.6 gallons. In arriving at this figure the population has been estimated at 550,000. Details of consumption are given in Tables XII and XIII.
Particulars of the quantity of water supplied by meters are also given in Table XIII, the amount of filtered water so supplied being 3,772.52 million gallons. 73.5% of the total consumption of filtered water was, therefore, accounted for by meters, compared with 67.8% in 1937. After making allowance for unmetered supplies given through public stand pipes, washing filters, mains and services, fires, etc., it is estimated that 76.1% of the total consumption was accounted for.
Samples of water were examined by the Government Bacteriologist with the following results :-
RAW WATER.
Total number of samples examined 96 Number shewing B.C.C. absent in 10 C.C. 10 (10.4%) Number shewing B.C.C. present in 10 C.C. or less 86 (89.6%)FILTERED WATER-UNCHLORINATED.
Total number of samples examined 107 Number shewing B.C.C. absent in 10 C.C. 85 (79.5%) Number shewing B.C.C. present in 10 C.C. or less... 22 (20.5%)TAP WATER-FILTERED AND CHLORINATED.
Total number of samples examined 964 Number shewing B.C.C. absent in 50 C.C. 864 (89.6%) Number shewing B.C.C. absent in 10 C.C. 78 (8.1%) Number shewing B.C.C. present in 10 C.C. or less... 22 (2.3%)The analyses by the Government Analyst shewed that the water was of good quality throughout the year. The city supply was treated with 7.26 tons of liquid chlorine and 4.3 tons of chloride of lime, which is equivalent to an average admixture of chlorine of about 0.555 of a part per million.
The formation of the waste detection branch referred to on page 17 of the 1937 report was approved by Government. As a first step three inspectors were engaged and employed on a house-to-house inspection of inside services. 14,203 inspections were made and 1,228 notices to repair defective services were served on consumers as a result of these inspections. Plans were prepared for the division of the distribution system on the island into fifty-four waste detection areas, each to be controlled by a waste detection meter, and twenty "Deacon" waste detection meters were provided. Schemes for the necessary alteration to mains, valves and sub-mains in each area were also prepared. Owing to lack of European staff, and to the water restrictions, only twelve night tests were carried out, but the results of these tests were highly satisfactory. Free tap re-washering was instituted in September, and 664 washers were fixed by the end of the year. Preparations were made to commence testing and stamping all fittings to be used on inside services on 1st January 1939.
The work of overhauling the valves on the mains in the city was continued. 205 were repaired on principal mains and eighty-three on sub-mains.
At the end of the year 43 public stand pipes, 205 pedestal fire hydrants and 670 underground hydrants were in use.
Particulars of main mileage on the island are given in Table XIV,