System Design Flow: 0 - 3,499 gallons per day
Regulatory Jurisdiction: Local Health Officer
Local Health Officer has authority and approval over systems with design flows through any common point up to 3,499 gallons per day.
System Design Flow: 3,500 - 100,000 gallons per day
Regulatory Jurisdiction: Department of Health Large On-site Sewage System Program
Washington State Department of Health LOSS Program per Chapter 70A.115 RCW, has authority and approval over:
- Wastewater treatment systems receiving domestic strength sewage at design flows from 3,500 to 100,000 gallons per day that use subsurface treatment or disposal. May include mechanical treatment.
- Any LOSS for which jurisdiction has been transferred to DOH from Ecology in accordance with the statute.
System Design Flow: Above 100,000 gallons per day
Regulatory Jurisdiction: Department of Ecology
Washington State Department of Ecology has authority and approval over:
- Domestic or industrial wastewater treatment under Chapter 173-240 WAC.
- Wastewater treatment systems with subsurface disposal and design flows above 100,000 gallons per day.
- Wastewater treatment systems with subsurface disposal that treat industrial waste.
- Wastewater treatment systems with subsurface disposal where the groundwater receiving effluent is in hydraulic continuity with surface water.
- Wastewater treatment systems with evaporative lagoons.
- Wastewater treatment systems receiving storm water discharges, including combined sanitary sewer and storm water systems.