The Safe Drinking Water Act (SDWA) defines the term "contaminant" as meaning any physical, chemical, biological, or radiological substance or matter in water. Some drinking water contaminants may be harmful if consumed at certain levels in drinking water while others may be harmless. The U.S. Environmental Protection Agency (EPA) set enforceable maximum contaminant levels (MCL) for approximately 90 contaminants in drinking water to protect against health risks. The Kansas Department of Health and Environment (KDHE) implements the regulations associated with these contaminants.
Unregulated contaminants are substances found in drinking water that do not have MCLs established by the EPA under SDWA. Some unregulated contaminants found in drinking water have non-enforceable health advisories published by EPA. Three of these include Harmful Algal Blooms (HAB), per-and polyfluoralkyl substances (PFAS) and manganese. The KDHE works with public water supply systems to address these unregulated contaminants when they are found in drinking water at levels above the EPA health advisory levels.