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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.
- Technical Guidance Manual for Individual and Subsurface Sewage Disposal Systems (Last updated: December 8, 2022)
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.
- Meeting Documents
- Request the previous meeting records using our Public Records Request form.
Current Updates to the Manual
| Year | Description |
|---|---|
| December 2022 | Section 4.2 At-Grade Soil Absorption System Section 4.3 Capping Fill System Section 4.24 Sand Mound |
| September 2022 | Section 1.4.2.1.1 Initial Septic Tank Approvals Section 1.4.2.3 Gravelless Product Approvals Section 2.2.4.1 Reduction to Separation Distance to Surface Water without a Variance |
| June 2022 | Section 4.20 Recreational Vehicle Dump Station (4-108 to 4-109) |
| 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
| Year | Description |
|---|---|
| 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 August | Section 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 January | Section 5.14. Updated products list in Table 5-15 (pp. 5-29 to 5-30) |
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Onsite Wastewater Coordinator