The cost of maintenance, for stand-pipe system, varies from 10 to 90 per cent. of revenue; for direct pumping, from 30 to 140 per cent. of revenue; for reservoir pumping, for large cities, from 12 to 37 per cent. of revenue; for small cities, from 12 to 120 per cent. of revenue; and new works, from 12 to 60 per cent. of revenue; for gravitation works, from 13 to 120 per cent. of revenue.
The revenue and the cost of maintenance (exclusive of interest), for each 1,000 gallons of water pumped, are respectively: Philadelphia, 5.77 and 1.28 cents; St. Louis, 6.91 and 2.55 cents; Chicago, 4.12 and 1.18 cents; Detroit, 4.09 and 82 cents; Buffalo, 3.50 and 1.00 cents; New York, 4.7 and one cent; Cleveland, 5.43 and 1.5 cents; Cincinnati, 7.01 and 2.6 cents.
The revenue received, for each 1,000 gallons delivered, is 15.52 cents at Liverpool, England; 14.35 cents at Berlin, Germany; 8.13 cents at Dresden, and 4 cents at Hamburg.
The comparative annual water-rent charges for a large house, in different cities, are as follows: Columbus, Ohio, $23.50; Lawrence, Mass., $20; Providence, R. I., $31; Brooklyn, $29.25; Buffalo, $43.50; Detroit, $23.25; Cincinnati, $28.73; Cleveland, $21.50; Chicago, $34; Philadelphia, $27.75; Pittsburgh, $71.50; Milwaukee, $34.50; Louisville, $51.50.
The meter rate charges, per 1,000 gallons, are 10 to 40 cents at Boston; 10 cents at Chicago; 10.2 at Cincinnati; 7 to 20 at Columbus, Ohio; 15 cents at Brooklyn; 13½ at Baltimore; 6 to 12 at Cleveland; 20 to 30 at Buffalo; 15 cents at Philadelphia; 7½ cents at New York; and 30 cents at Providence, Rhode Island.
The meter rates, per 1,000 U. S. gallons, at Stuttgart, Germany, are 11 cents for filtered river water, 5½ cents for lake water, and 15 cents for spring water. The rates, at Frankfort-on-the-Main, are 3.7 to 5 cents; at Hamburg, Germany, 8½ cents; at Leipsic, 7½ to 9¼ cents; at Berlin, Germany, 6½ to 25½ cents; at Dublin, Ireland, 6½ to 11 cents; and at Glasgow, Scotland, 15 cents per 1,000 U. S. gallons.
The average dividend paid by the water companies of Great Britain, in 1870, was 7 per cent.
The different kinds of water pipes in use are made of wood, cast-iron, wrought-iron, and glass. For adapting wrought pipe to practical use, various methods have been resorted to, that of coating with asphaltum, enameling, galvanizing, and lining inside and covering outside with cement. The latter method has been adopted by a number of water-works; but the liability to corrosion, from imperfect work and material, has caused its abandonment in a number of places. The Spring Valley Water Company, of San Francisco, have in use a number of wrought-iron riveted pipes, coated with asphaltum, of 20 to 42 inches in diameter. They are made of No. 12 to 14 iron (Birmingham wire gauge), and have a hydrostatic pressure upon them of from 200 to 400 feet. Virginia City (Nevada) water-works laid two lines of wrought-iron pipe across the Washoe Valley, 7½ miles wide--one of 12-inch riveted pipe, and the other of 10-inch enameled, lap-welded tubes. The pressure on the pipe at the bottom of the valley is 750 pounds. The enormous pressure has caused a number of rivets to give out. On the test for the respective capacities, the 10-inch pipe delivered 2½ millions per day, against two millions for the 12-inch pipe.
