SC S0139

Requires holders of NPDES (National Pollutant Discharge Elimination System) permits that discharge effluent into South Carolina waters to post conspicuous signs at discharge outlets

Signs must be at least 18 inches square, weather-durable, and display: "Treated Wastewater" or "Cooling Water," permittee and facility name, permit number, permittee phone number, and department reporting number

Exempts stormwater-only discharges and certain general permits including hydroelectric facilities, hydrostatic test water, vehicle wash water, potable water treatment plants, and pesticide applications

Permits waivers if signage conflicts with other laws, outlets are on restricted property, signs cannot be reasonably maintained, signs serve no public purpose, or discharges are temporary

Signs must be posted within 12 months of the act's effective date, and the department must notify all permit holders of requirements by November 29, 2025