(a) Water shall be pronounced unfit for human consumption:
(1) When the total number of bacteria in the water exceeds 100 per cubic centimeter; provided that the water shall be planted on standard agar plates, incubated 24 hours at 37°C temperature, and that the estimate shall be made from not less than two such plates; and
(2) When the organisms of the colon bacillus group are present in one cubic centimeter or in at least two of every three 10-cubic centimeter portions of such water, planted in fermentation tubes containing lactose peptone broth, within 24 hours of incubation at 37°C.
(b) The following shall be considered sufficient evidence of the presence of organisms of the colon bacillus group within 24 hours of incubation at 37°C:
(1) The appearance of red, acid forming colonies of bacteria on Endo’s medium plates; and
(2) The formation of gas in fermentation tubes containing lactose peptone broth.
(c) The culture medium used for these tests shall be prepared in accordance with standard methods of water analysis of the American Public Health Association, as set forth in the last revision of Standard Methods of Water Analysis.
(Ord. 9, passed 8-21-1917)