Water quality within the United States is highly regulated, involving strict guidelines and water quality testing. As a result, drinking water in the United States is among the safest to drink in the world. Although water quality in the United States is high, there are still some underlying problems. Therefore, both local and federal governments work constantly to ensure everyone in the community has safe drinking water.

Drinking water comes from two major sources. Surface water such as lakes, rivers, and reservoirs provides much of the water used as drinking water. Groundwater, which is pumped from wells, is also a source of drinking water commonly used in rural areas.

Surface water typically requires both filtration and disinfection in order to reach drinking water quality standards. Groundwater is considered to be the purest source of water. This is because it is naturally filtered when it passes through the layers of rock and sediment in an aquifer. Today, the Environmental Protection Agency (EPA) and water quality standards ensure groundwater undergoes technological treatment as well. Most water systems add chlorine or other disinfectants to purify the water within the water distribution system and to ensure the highest water quality.

Local community water suppliers, such as cities, are also required to provide an annual water quality report to their customers. They do this so the consumer can be a "watch dog" when it comes to the safety levels of their drinking water. The reports provide information on local drinking water, including the water's source and the contaminants found in the water.

According to the EPA, water quality standards are the foundation of the water quality-based control program mandated by the Clean Water Act. A water quality standard consists of four basic elements. First, it designates uses of the water body. Next, it creates water quality criteria to protect designated uses. Third, it sets forth an antidegradation policy to maintain and protect existing uses and high quality waters. Finally, it sets general policies addressing implementation issues.