Of all the contaminants in the water supply, bacteria is the hardest to control. In fact, bacteria are such good survivors that they can live in RO water, which has very few nutrients in it to sustain them. Bacteria do this by flipping a DNA “switch” which puts them into low nutrient mode. In this mode they get smaller, more spherical and bond to the internal surfaces of watering systems. They will then secrete slimey glycocalyx to protect them.

Bacteria will attach to any surface that water contacts and develop a biofilm. When you remove a stopper from a water bottle that has been on a cage for a few days, it will feel slippery. That slippery feeling is due to a biofilm - a colony of bacteria that has set up its own microscopic “city” on the stopper. Biofilm development can also occur in watering system piping. And as the biofilm grows, pieces of it can detach, flow downstream to be consumed by the animals.

To control free floating bacteria, it is important to treat the water with a residual disinfectant. When combined with automated flushing, low residual chlorination (2-3ppm) or acidification (2.6-3pH) are very effective in controlling bacteria.