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Septic Technical Guidance Committee

The Technical Guidance Committee (TGC) is responsible for maintaining the Technical Guidance Manual, reviewing best management practices for individual and subsurface sewage disposal, and providing recommendations on variances and commercially manufactured wastewater treatment components and systems. The TGC comprises six members: one DEQ representative (chair), three health district representatives, one State of Idaho-licensed professional engineer, and one licensed installer. TGC meetings occur quarterly unless, a special issue warrants a special meeting.

The Technical Guidance Manual provides guidance on the design, construction, alteration, repair, operation, and maintenance of standard individual and subsurface sewage systems, their components, and alternatives. The manual is updated periodically to adapt to the dynamic and complex nature of small wastewater disposal systems. Updates are cited below.

Note: This is a large file. If you have difficulty downloading it, try opening it in a different browser or from your hard drive instead of your browser. Right-click on the link, select “Save link as,” navigate to the file on your hard drive, and double-click to open.

Current Updates to the Manual

Year Description
March 2023 Section 5.2 Approved Septic Tanks
Section 5.4 Extended Treatment Package Systems
Section 5.13 Proprietary Wastewater Treatment Products
Section 4.3.5 Capping Fill System Construction

Previous Updates to the Manual

December 2022Section 4.2 At-Grade Soil Absorption System
Section 4.3 Capping Fill System
Section 4.24 Sand Mound
September 2022

Section Initial Septic Tank Approvals

Section Gravelless Product Approvals

Section Reduction to Separation Distance to Surface Water without a Variance

June 2022Section 4.20 Recreational Vehicle Dump Station
February 2022

Section 2.1.2 Soil Design Groups and Subgroups
Section Reduction in Separation Distance to Surface Water without a Variance

Section 4.12 Grey Water Sump

Section 4.15 Wastewater Incinerator 

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Onsite Wastewater Coordinator

Peter Adams
(208) 954-1438

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