Microorganisms: Microorganisms usually enter water
tanks carried by aquifer sediments and improperly sealed
tank covers or breathing outlets improperly designed or not
fitted with particle filters. Arizona’s dusty environment often
generates significant amounts of dust, which can enter water
tanks and contaminate the water with several organisms
including: green algae, bacteria, viruses, protozoa, fungi,
pollen, and spores. Potable water often contains sufficient
nutrients (nitrate, phosphate, and other minerals) to allow for
growth of green algae (some light is needed) and filamentous
bacteria, which produce slime (biofilm) (Fig 4). Although
many bacteria that are naturally occurring in water are not
usually harmful, pathogenic bacteria, viruses, and parasites