“The EPA regulates water pollution under the auspices of the Clean Water Act, the Safe Drinking Water Act and other environmental laws. With the help of state and local authorities, the EPA establishes water quality standards, promotes guidelines for best management practices, and issues permits to point source polluters and treatment facilities. The Agency also offers compliance assistance to the regulated community and seeks punitive legal action against violators of water pollution laws and regulations.”

Anyone who discharges into a river must obtain a permit or waiver and there are limits on the species that can be discharged into the river. These are called water quality standards (third reference).