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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.

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Current Updates to the Manual

YearDescription
February 2022

Section 2.1.2 Soil Design Groups and Subgroups (2-6)

Section 2.2.4.1 Reduction in Separation Distance to Surface Water without a Variance (2-10 to 2-11)

Section 4.12 Grey Water Sump (4-69)

Section 4.15 Wastewater Incinerator (4-80 to 4-82)

Previous Updates to the Manual

YearDescription
November 2021

Section 1.4.2.4 Proprietary Wastewater Treatment Product Approval Policy (1-10 to 1-11)

Section 1.8.3 Property Access & Use (Easements) Restrictions (1-20 to 1-22)

Section 4.16.2 Individual Lagoon Approval Conditions (4-82 to 4-85)

Section 4.17.2 Pit Privy Approval Conditions (4-86 to 4-87)

Section 4.29.2 Vault Privy Approval Conditions (4-174 to 4-175)

May 2021

Section 1.4.2.2.1 Provisional ETPS Approval (1-6 to 1-7)

Section 1.4.2.2.2 General ETPS Approval (1-7 to 1-9)

Section 1.8 Property Access & Use (Easements) (1-20 to 1-22)

Section 4.8.2 ETPS Approval Conditions (4-53 to 4-54)

Section 4.23.3.1 Standard In-Trench Sand Filter Design & Construction (4-135)

2021 February

Section 1.4.2.4 Proprietary Wastewater Treatment Product Approval Policy (pp. 1-10)

Section 4.19.3.6 Pump to Gravity Distribution (pp. 4-104 to 4-105)

2020 November

Section 1.8 Easement (pp. 1-18 to 1-20)

Section 4.3.3 Above-Grade Capping Fill System (p. 4-19)

2020 AugustSection 1.5.1 Installer’s Registration Permit and Service
Provider Certification Application, Bond, Fee, Training, and Exam (pp. 1-10 to 1-11)Section 4.19.3.2 Pressurization Unit (pp. 4-95 to 4-96)
2020 May

Section 3.2.8.1.2 Medium Sand (p. 3-17)

Section 1.4.2.2.1 Provisional ETPS Approval (pp. 1-6 to 1-7)

Section 4.8.2 Extended Treatment Package System Approval Conditions (pp. 4-53 to 4-56)

Section 4.13 Gray Water System (pp. 4-71 to 4-77)

2019 December

Section 1.4.2.1.1 Initial Septic Tank Approvals (p. 1-4)

Section 3.2.3 Septic Tank and Dosing Chamber Installation (p. 3-6)

Section 5.8 Septic Tank Effluent Filters, Table 5-12 (p. 5-23)

2019 October

Section 4.23.3.2.1 Standard Enveloped In-Trench Filter Design and Construction. Figure 4-39. (p. 4-136)

Section 4.23.3.2.2. Pretreated Enveloped In-Trench Sand Filter Design and Construction. Figure 4-40. (p. 4-137)

Section 4.23.3.2.3. Pressurized Enveloped In-Trench Sand Filter Design and Construction. Figure 4.41. (p. 4-138)

Section 5.2. Approved Septic Tanks. Table 5-1. (p. 5-2)

Section 5.11. Drainfield Remediation Components. Table 5-15. (p. 5-27)

Section 5.13. Proprietary Wastewater Treatment Products. Table 5-17. (pp.5-29–5-30)

2019 July

Section 2.2.5. Method of 72 to Determine Effective Soil Depths (pp. 5-17 to 5-19)

Section 4.23. In-Trench Sand Filter (pp. 4-133 to 4-138)

Section 5.2. Approved Septic Tanks, Table 5-1 (pp. 5-2 to 5-11)

Section 5.4. Extended Treatment Package Systems, Table 5-3 (pp. 5-13 to 5-15)

Section 5.5. Approved Nondischarging Products, Table 5-5 (p. 5-17)

2019 March

Section 1.9.5. Property Owner Operation, Maintenance, or Monitoring Requirements (pp. 1-31 and 1-32)

Section 4.24.3.1. Sand Mound Absorption Bed Cell Design (p. 4-141)

Section 5.2. Approved Septic Tanks, Table 5-1 (pp. 5-2 to 5-10)

Section 5.5. Approved Nondischarging Products, Tables 5-5 to 5-8 (pp. 5-17 to 5-19)

Section 5.13. Proprietary Wastewater Treatment Products, Table 5-13 (pp. 5-29 and 5-30)

2019 JanuarySection 5.14. Updated products list in Table 5-15 (pp. 5-29 to 5-30)

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Onsite Wastewater Coordinator

Peter Adams
peter.adams@deq.idaho.gov
(208) 373-0464

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