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Water Quality Program

Wastewater Discharge Permits in Washington State

What is a Wastewater Permit?

A wastewater discharge permit is a legal document issued by the Ecology to control the discharge of wastewater to surface and ground waters and to publicly-owned sewage systems

Environmental scientists and engineers write permits. Permits limit the amount and concentrations of contaminants that a facility may discharge and may impose operating conditions when necessary. Permits generally include monitoring and reporting requirements and may include spill prevention planning, and other regulatory activities. Most permits have a five-year lifespan.

Permit cover.  Photo courtesy of Sandy Howard, Washington Department of Ecology.

Principles of the Permit Program

Our goal is to maintain the quality of state waters by limiting pollutant discharges to the greatest extent possible. Four principles drive the wastewater discharge permit program toward that goal:

  • Discharging pollutants is not a right. A permit is required to use the waters of the state, which are a public resource, for wastewater discharge.
  • Permits limit the amount of pollutants that a facility may discharge.
  • Wastewater must be treated with all known available and reasonable technology (AKART) before it discharges, regardless of the quality of water into which it is discharged.
  • Effluent limits are set using technology-based and water quality-based standards. The more stringent of the two limits is always applied.

Who Needs a Permit?

State permits are required for anyone who discharges waste materials from a commercial, industrial, or municipal operation to ground or to a publicly-owned treatment plant. NPDES permits are required for anyone who discharges to, or has a significant potential to impact, surface waters.

Types of Permits

Ecology issues two types of wastewater discharge permits:

  • Individual permits, which cover specific facilities or activities like factories.
  • General permits, which cover a category of similar dischargers (e.g., boatyards).

Either permit type may be issued as a state permit (ground water only) or a combined state/NPDES permit for dischargers to both ground water and surface water.

More on Permits

What is a Permit Fact Sheet?
Public Involvement Opportunities
History of the Permit Program


Last updated September 2014


More on specific general water quality permits

Search for specific individual water quality permits - Permit Reporting and Information System (PARIS)

Guidance and tools used by Ecology in developing water quality permits






Contact Regional Permit Coordinators for questions on specific permits.

For general questions on wastewater permitting please contact:

Vincent McGowan
Water Quality Program

Nat Kale
Water Quality Program