What type of approval must bleach used in public water systems have?

Bleach used in public water systems must have NSF approval. The NSF (National Sanitation Foundation) certification indicates that a product has been tested and meets specific public health and safety standards, particularly regarding its suitability for use in drinking water applications. This is crucial because bleach, or sodium hypochlorite, is often employed in water treatment processes to disinfect and ensure the water is free of harmful microorganisms.

NSF certification ensures that the bleach does not introduce any harmful contaminants into the water supply and confirms that it meets the necessary health safety standards. This is particularly important for public water systems, where the health of a large population depends on the quality of the water they receive.

Other options, while relevant in different contexts, do not specifically govern the use of bleach in water treatment. FDA approval pertains to food and drug safety rather than water treatment chemicals, EPA approval relates to environmental safety and regulations but does not directly certify the individual products, and ISO certification generally recognizes quality management systems rather than specific product suitability for public health uses. Therefore, NSF approval is the most applicable and essential requirement for bleach used in public water systems.