Protecting Public Health and the Environment.

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.

Current Year's Updates to the Manual

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)
Section 1.9.5. Property Owner Operation, Maintenance, or Monitoring Requirements (pp. 1-31 and 1-32)
Section 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)
Section 5.14. Updated products list in Table 5-15 (pp. 5-29 to 5-30)

Previous Years' Updates to the Manual

Section 4.5.2. Updated site and soil characteristics. (pp. 4-24 and 4-25)
Section Updated design and construction requirements. (pp. 4-137 and 4-138)
Section 5.2. Corrected approval information in Table 5-1. (pp. 5-4 and 5-7)
Section 5.4. Updated products list in Table 5-3 (p. 5-14)
Section 5.5. Reviewed and updated Table 5-5. (p. 5-17)
Section 5.13. Updated products list in Table 5-14. (p. 5-28)
Section 5.14. Updated products list in Table 5-15 (p. 5-29)
Section 1.9.1. Added Item 2 items for OnlineRME. (p. 1-20)
Section 1.9.3. Revised section for Online RME. (pp. 1-26 and 1-27)
Section Deleted Item 4 on separation determination guidance. (p. 2-13)
Section 5.2. Added tanks and removed them from the approved septic tank table. (p. 5-2 and pp. 5-6 and 5-9)
Section 5.4. Changed addresses. (p. 5-14 and p. 5-17)
Section 4.13.3. Updated design requirements. (p. 4-72)
Section 4.26.3. Corrected equation 4-16. (p. 4-154)
Section 5.4. Updated table 5-3, ETPS manufacturer's list. (p. 5-16)
Section 5.11. Updated table 5-12, manufacturer's list. (p. 5-27)
Section 5.13. Provided clarification in footnote table 5-14. (p. 5-29)
Section 5.14. Updated products list in table 5-15. (p. 5-30)
Section 7. Deleted rules and code text and provided links to current rules and code. (p. 7-1)

Technical Guidance Committee

Next Scheduled Meeting Date

Wednesday, December 04, 2019, 9:30 a.m.
DEQ State Office
Conference Room D
1410 N. Hilton, Boise

Agenda and Appendices

Meeting Minutes

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


Page Subscription

Staff Contacts

On-Site Wastewater Analyst
Rachael Smith
DEQ State Office
Water Quality Division
1410 N. Hilton
Boise, ID 83706
(208) 373-0249

Health District Contacts

For questions regarding a proposed or existing on-site wastewater system permit or inspection, please contact your local public health district.

DEQ Resources

More Information

Individual/Subsurface Sewage Disposal Rules

Idaho Code Related to Individual and Subsurface Sewage Disposal Systems

Rules Governing the Cleaning of Septic Tanks

Related Pages

On-Site Wastewater Systems (Septic Systems)

Extended Treatment Package Systems (Aerobic Treatment Units)

For Engineers and Developers