What defines an approved water supply?

An approved water supply is defined as one that is regulated by a state or local health agency. This regulation ensures that the water meets specific quality and safety standards set forth for public health. Agencies are responsible for overseeing various aspects of water quality, including monitoring for contaminants and ensuring that treatment processes are effective in producing safe drinking water.

The other options do not fully capture what constitutes an approved water supply. For instance, while chemical treatment is often a part of ensuring water quality, simply being treated with chemicals does not guarantee the supply is approved without the oversight and regulation of health agencies. Additionally, a water supply sourced only from surface water is not by itself an indicator of approval; groundwater sources can also be approved when they meet the necessary standards. Lastly, the source of supply being exclusively from private companies does not inherently imply that the water is safe or approved, as the focus is on the regulatory oversight rather than the ownership of the supply source. Thus, regulation by health authorities is the critical factor that defines an approved water supply.