Drinking-water quality and issues associated with water vending machines in the city of Los Angeles.

The study reported in this paper sampled 40 water vending machines distributed throughout the city of Los Angeles, California, in the water servicing area of the Los Angeles Department of Water and Power. The authors examined water samples for temperature, turbidity, chlorine content, fungal growth, coliform bacteria, fecal coliform bacteria, Pseudomonas spp., Pseudomonas aeruginosa, and heterotrophic plate counts using plate count agar and R2A agar. Roughly 48 percent of the original 40 samples were sampled in a second or third round, and these subsequent samples were examined for coliform bacteria, fecal coliform bacteria, Pseudomonas spp., Pseudomonas aeruginosa, and both heterotrophic plate counts. Observations were made of vending-machine external conditions, identifying information, and permits. Statistically significant associations were found between operator accessibility and poor machine conditions, operator accessibility and permits, and operator accessibility and the servicing interval. Statistically significant associations also were found between operator accessibility and presence of fungi, Pseudomonas spp., and Pseudomonas aeruginosa, and between presence of fungi and the servicing interval. In addition, statistically significant associations indicate that the quality of machine maintenance is a factor in microbial levels. The microbial content of the water suggested a need for further research into potential health effects in susceptible populations.