=24. Character of District.=—The various sections of a city are classified as commercial, industrial, or residential. The residential districts can be subdivided into sparsely populated, moderately populated, crowded, wealthy, poor, etc. Commercial districts may be either retail stores, office buildings, or wholesale houses. Industrial districts may be either large factories, foundries, etc., or they may be made up of small industries housed in loft buildings. In cities of less than 30,000 population the refinement of such subdivisions is generally unnecessary in the study of sewage flow, all districts being considered the same. The data given in Tables 8 and 9 indicate the difference to be found in different districts of large cities. The Milwaukee data are presented in a form available for estimates on different bases. These data are shown in Table 10. TABLE 7 RATES OF WATER CONSUMPTION From Journals of American and New England Water Works Associations ───────────────────────────────────┬───────────┬───────────┬─────────── City │Population │ Per Cent │Consumption, │ in │ Metered │ Gal. per │ Thousands │ │Capita per │ │ │ Day ───────────────────────────────────┼───────────┼───────────┼─────────── Tacoma, Wash. │ 100 │ 11.6│ 460 Buffalo, N. Y. │ 450 │ 4.9│ 310 Cheyenne, Wyo. │ 13 │ │ 270 Erie, Pa. │ 72 │ 3.0│ 198 Philadelphia, Pa. │ 1611 │ 4.6│ 180 St. Catherines, Ont. │ 17 │ 3.2│ 160 Port Arthur, Ont. │ 18 │ 14.7│ 145 Ogdensburg, N. Y. │ 18 │ 0.2│ 140 Los Angeles, Cal. │ 516 │ 77.9│ 140 Wilmington, Del. │ 92 │ 43.7│ 125 Lancaster Pa. │ 60 │ 34.6│ 120 Richmond, Va. │ 120 │ 75.2│ 115 St. Louis, Mo. │ 730 │ 6.7│ 110 Springfield, Mass. │ 100 │ 94.4│ 110 Keokuk, Ia. │ 14 │ 64.5│ 105 Jefferson City, Mo. │ 13.5│ 34.4│ 100 Muncie, Ind. │ 30 │ 23.8│ 95 Burlington, Ia. │ 24 │ 4.5│ 90 Council Bluffs, Ia. │ 32 │ 75.5│ 80 San Diego, Cal. │ 85 │ 100 │ 80 Monroe, Wis. │ 3 │ 100 │ 80