Rain water tanks are vulnerable to contamination. They contain water that has run-off the roof. Roofs and gutters have organic matter such as leaves, animal poo and dead insects at the very least. This organic matter decays and becomes the perfect breeding ground for bacteria, virus and micro-organisms.
Water Tanks also contains water in a enclosed area making it the perfect environment for the growth and development of germs. The germs can not spread out. They become concentrated within your water tank. Particular types and amount of germs will cause health problems.
Great Water Filters sell the Elite Series 4 UV Light Under Sink Water Filter that will protect you and your family against the dangers of germs. You can upgrade any of the Elite Series to have a UV light filter. The Elite Series 5 Whole House Water Filter System offers an upgrade that will be especially beneficial if you source your water from an untreated supply. Ultra Violet Light water treatment comes highly recommended.