Types of Discharge Approvals

The Industrial Waste Program issues several types of approvals to industries discharging into the King County wastewater treatment system. The type of approval is determined by the nature of the business, the volume and characteristics of wastewater, and potential risk to the system. Types of approvals are:

PERMIT

• Wastewater discharge generally greater than 25,000 gallons per day (gpd) or
• Federally required industry (categorical industry)

DISCHARGE AUTHORIZATION

• Wastewater discharge generally less than 25,000 gpd, but more than 1,000 gpd

LETTER OF AUTHORIZATION

• Wastewater discharge generally less than 1,000 gpd

VERBAL AUTHORIZATION

• Small and one-time discharges

Before discharging any industrial waste to the sewer (waste from toilets is not included), a business must contact the Industrial Waste Program to obtain the proper authorization. Please call 206-263-3000.