Potable water is safe for human consumption and is generally monitored by the EPA. The EPA monitors all public water systems in the United States, while individual water systems (typically well systems) are not monitored. It requires a substantial input of energy to produce potable water, and there are limited resources for potable water in many areas of the country. Potable water is used in nearly all household applications as well as cooling and heating operations. More information can be found from the CDC or the EPA.