Why is Stormwater Discharge a Concern?

Since 1972, the EPA's Clean Water Act has prohibited the discharge of any pollutant to waters of the United States . Each state and municipal regulatory requirements pertaining to stormwater is based upon this federal regulation with additional provisions to address specific needs and conditions of watersheds within a region.

Runoff in areas where stormwater flows onto impervious surfaces, such as on concrete and asphalt paved areas, can cause the stormwater to flow into storm drains. Some storm drain systems discharge untreated water directly to creeks, rivers, lakes, and wetlands. Discharging polluted stormwater into this type of storm drain system is the same as discharging wastewater directly into a water body. State and federal regulations (specifically The Clean Water Act 40 CFR) are enforced to eliminate this form and other forms of water pollution.

Stormwater can contain high concentrations of oil and grease, heavy metals, detergents that may contain phosphates and suspended solids. Detergents, even biodegradable detergents, can be poisonous to fish. Phosphates, an ingredient in some detergents, are plant nutrients that can cause the excessive growth of nuisance plants when the phosphates enter lakes and streams. Stormwater can also contain dirt and pollutants from vehicles and equipment washing.