TABLE 16.—Principal Items of Expenditure.
| Pesos, Mexican currency. | ||
| Estanzuela Supply: | ||
| Aqueduct and dam | 502,000 | |
| South Reservoir | 429,000 | |
| ——— | 931,000 | |
| San Geronimo Gravity Supply: | ||
| Aqueduct, tunnel, and infiltration gallery | 223,000 | |
| Obispado Reservoir | 436,000 | |
| ——— | 659,000 | |
| San Geronimo Provisional Supply, | ||
| including boring operations, etc. | 130,000 | |
| City Water Distribution System | 1,195,700 | |
| City Sewer System | 1,036,000 | |
| Outfall: | ||
| Main outfall sewer | 425,000 | |
| Sewage purification works | 75,000 | |
| ——— | 500,000 | |
| ————— | ||
| Total | 4,451,700 |
As a general statement, the actual cost of labor is about 331⁄3% of the total cost of the construction work, including materials. Fig. 20 shows in graphic form the amount of the labor pay-rolls and the progress of the work during the whole construction period from 1906 to 1909, inclusive, comprising also that done under contract.
Fig. 20.—Progress diagram showing monthly labor pay-rolls during the construction period.
Tariffs and Sanitary Regulations.
Tariffs.—The tariffs charged for the water and drainage service (Table 17) were approved by the State Government (which accepts the responsibility for their collection), under a compulsory State law which came into force on March 1st, 1910, for the southern portion of the city, and on July 1st, for the northern half, the penalty for non-compliance being a tax of 10% on the monthly rental value of the property, as assessed by the State officials.
The basis of the tariffs (which were published on February 22d, 1909) is a charge for water varying between 12 and 16 cents (Mexican) per 1,000 liters, with a minimum monthly rate for each different class of property connected to the system. The rate for house drainage is fixed at 80% of the minimum water rate levied on the consumer. The minimum rates have been fixed so that the poorer classes of the community
will not be overtaxed, while at the same time the rate is actually levied on the quantity of water used, as indicated by the meter. All the services at the present time are metered, and the meter system will be used throughout.
TABLE 17.—The Tariffs.