water can become contaminated with very serious microbial contaminants, such as Salmonella, Shigella, cholera, Campylobacter, enteroviruses, Cryptosporidium, and Giardia ,as further describedby McAllister and Topp(2012) in the present issue. All can pose serious threats to the health and well-being of pigs. Chlorination, or another from of disinfection, can control some organisms but not all, so water supplies need to be carefully