Of all the inhabitants of the microbial world, viruses are the smallest--as tiny as 10 nanometers. Microbiological contamination of water has long been a concern to the public. Viruses, including hepatitis A virus, rotaviruses, and Norwalk and other caliciviruses, are microbes that can cause illness. EPA regulates viruses in drinking water by requiring water systems that use surface water (or ground water under the direct influence of surface water) to treat their water to ensure that 99.99% of viruses are rendered harmless or physically removed.
The recommended method for Virus Water Purification for private wells is Ultra Violet Filtration
. UV Disinfection has an effective kill rate of 99.99% of most living microorganisms such as bacteria & viruses.