Technical Guidance Manual for Individual and Subsurface Sewage Disposal Systems

This document 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.

Technical Guidance Manual for Individual and Subsurface Sewage Disposal Systems (Last updated: March 30, 2012)

Updates to the Manual

2012: Description
March: Section 4.7. Drip Distribution Systems (pp. 4-9 - 4.13c); Section 4.20. Pressure Distribution System (p. 4-52)

2011: Description
October: Section 4.30. Addition of Table 4-25. (p. 4-90)
August: Section 2.2. Restored heading and first paragraph inadvertently omitted during previous revision (p. 2-7)
July: Section 2.1. Soils Texture and Group Determinations updated to include a new revised triangle and new flowchart for soil texture determination (pp. 2-1 - 2-6); Updated list of Approved Septic Tanks (Table 5-3, p. 5-3)
June: Section 4.11. Extra Drain Rock Trench, revised and renamed: 4.11 Extra Drainrock Drainfield (pp. 4-32 - 4-34); New Drainfield Remediation Components (pp. 87 - 4-88, 5-26)
April: Corrected Page Reference in Footnotes a & b (p. 5-24)
March: Chapter 8 Formatting/Numbering Issues Resolved (pp. 8-1 - 8-43)
January: ETPS Individual System Sampling Process (p. 4-30)

2010: Description
December: Incinerating Toilets (p. 5-17)
July: Extended Treatment Package Systems (pp. 5-11 - 5-15)
June: Extend Treatment Package System (pp. 4-25 - 4-31); Approved Septic Tanks: Updated List (pp. 5-4 - 5-5)
May: Extended Treatment Package Systems (pp. 5-11 - 5-15); Total Nitrogen Reduction Policy (p. 8-48)

2009: Description
November: Approved Septic Tanks: Updated List (pp. 5-4 - 5-5); Gravelless Trench Components (pp. 5-3 - 5-10); Extended Treatment Package Systems (pp. 5-11 - 5-15)
September: Extra Drain Rock Trench (pp. 4-32 - 4-33); Standard Percolation Test: Updated (p. 2-9)
June: Approved Septic Tanks: Updated List (pp. 76-1 - 76-7); Approved Vault Toilets (p. 78-7)
May: Approved Septic Tanks: Updated List (pp. 76-1 - 76-7)
April: Approved Septic Tanks: Updated List (pp. 76-1 - 76-7)
February: Total Nitrogen Reduction Policy (p. 155)
January: Table 8. Constituent Mass Loadings and Concentrations in Typical xtended Treatment Package Systems (p. 39)

For updates made 2000-08, contact the On-Site Wastewater Coordinator.

Technical Guidance Committee

Next Scheduled Meeting Date

June 19, 2012, 9 a.m. - 4 p.m.
DEQ State Office
1410 N. Hilton
Boise, ID
Agenda pending

Meeting Minutes

For previous meeting minutes, contact the On-Site Wastewater Coordinator.

Department of
Environmental Quality

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