Water quality individual permit guidance

The Permit Writer’s Manual (Ecology Publication Number 92-109) is meant to guide permit writers and the public through our process of developing and issuing wastewater discharge permits.

• Permit Writer's Manual Appendices include specific technical guidance for the individual permitting process.
• PermitCalc Workbook contains a complete list of useful spreadsheets and instructions for NPDES permit writers in the "intro" tab. Please contact your permit manager for a current copy of the Excel workbook. 

Wastewater comes from water used in industries, businesses, or homes. We regulate these discharges to protect surface and groundwater. Permit writers develop permit limits from facility-specific discharge quality information and water quality standards.

• All domestic wastewater treatment plants must meet minimum performance standards, known as technology-based effluent limits.
• Water quality-based effluent limits based on surface water quality criteria may be necessary for some NPDES permits.
• Application of Water Quality Criteria in Brackish Waters includes thresholds for areas where freshwater/marine water standards apply (usually in estuaries) in NPDES permits.
• Implementation Guidance for the Ground Water Quality Standards promotes consistent application of standards for discharges to ground.

These documents assist all permittees in design development of conveyance, treatment, and discharge infrastructure.

• Criteria for Sewage Works Design, also known as the "Orange Book," contains domestic wastewater treatment design guidance.
• Pipeline Separation Design and Installation Reference Guide (Version 9) describes required separations between wastewater and potable water infrastructure.
• Infiltration/Inflow Guidance is EPA's brochure about infiltration/inflow analysis and project certification.
• Guidance on Land Treatment of Nutrients in Wastewater, with Emphasis on Nitrogen.
• Irrigation Management Practices to Protect Ground Water and Surface Water Quality
• Vehicle and Equipment Washwater Discharges includes best management practices.

We are updating the Design Criteria for Municipal Wastewater Land Treatment Systems for Public Health Protection, also called the "Green Book."

Quality Assurance Project Plans (QAPPs) ensure systematic data collection that meets our standards and provides credible environmental data.

• Quality Assurance Project Plan (Template) for Temperature Study – Municipal
• Quality Assurance Project Plan (Template) for Temperature Study – Industrial
• Quality Assurance Project Plan (Template) for receiving water studies

Engineering reports, plans, and specifications must meet requirements of Chapter 173-240 WAC before approval.

• Guidelines for Preparation of Engineering Reports for Industrial Wastewater Land Application Systems
• State Requirements for Submission of Engineering Reports and Plans for Industrial Wastewater Treatment Facilities

Resources for delegated pretreatment programs and permittees that must conduct industrial user surveys.

• Guidance Manual for Performing an Industrial User Survey

We require all permittees to report permit data electronically. 

• Water quality permits database – Permit and Reporting Information System (PARIS) contains information about water quality permits, inspections, enforcement actions, and discharge monitoring reports (DMRs).
• Water quality web portal guidance helps permittees apply for permits, report discharge data, and submit other documents electronically to the WQWebPortal.

• Stormwater permit types and guidance
• Reclaimed water permit guidance