What does the Surface Water Treatment Rule require for surface water supply systems?

The Surface Water Treatment Rule (SWTR) is designed to ensure that drinking water derived from surface water sources is adequately treated to protect public health. One of the central requirements of the SWTR is that all systems using surface water must provide disinfection to effectively eliminate pathogens that can be present in such sources, notably Giardia lamblia, which is a protozoan parasite that can cause gastrointestinal illness.

Disinfection serves as a critical barrier against these health risks, which is why this answer is the correct choice. Systems are required to implement treatment processes that can sufficiently inactivate or remove these pathogens, providing assurance that the water is safe for consumption.

While alternatives such as regular chemical softening, filtration of all water supplies, and removal of iron and manganese are important for various aspects of water treatment and quality, they do not specifically address the key requirement of pathogen removal as mandated by the SWTR. Effective disinfection remains essential for maintaining public health standards for water quality.