The quality standard for public water supplies is primarily based on the use of water for:

The quality standard for public water supplies is primarily focused on drinking water because safe drinking water is essential for public health. Standards are set to ensure that water is free from harmful microorganisms, chemicals, and other contaminants that could pose health risks to the population. Regulatory agencies, such as the Environmental Protection Agency (EPA) and state health departments, establish guidelines and treatment processes specifically aimed at making water potable for human consumption.

While water might be used for swimming, agriculture, and industrial purposes, the highest level of quality control is essential for drinking water to prevent waterborne diseases and other health issues. This focus on drinking water quality reflects the understanding of its direct impact on human health and well-being, making it the primary concern when establishing water quality standards.