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.

Updates to the Manual

2013
Description
June
Section 5.2. Approved Septic Tanks. Added septic tank to the Wilbert Precast listing (1-piece, 2-compartment tank) in Table 5-1. (pp. 5-10 - 5-11)
May
Section 4.15. Emergency Holding Tank. Entire section was updated to reflect the intended use of holding tanks for emergency situations only. (pp. 4-54 - 4-55)
Section 4.20.3.6. Pump to Drop Box. New subsection to section 4.20 providing guidance on pumping effluent to a different elevation for gravity dispersal through the drainfield. (p. 4-76)
Section 4.21. Recreational Vehicle Dump Station. Entire section updated to provide guidance on these installations and separate the requirements from section 4.15 of the TGM. (pp. 4-77 - 4-78)
Section 4.26. Seepage Pit/Bed. Entire section updated to expand guidance regarding the use of seepage pits in health districts 1-6 and provide expanded guidance on seepage bed type installations. (pp. 4-96 - 4-98)
Section 5.9 Pipe Materials for Specified Uses. Section updated to include a new type of pipe allowed for installation in subsurface sewage disposal systems. (p. 5-25)
April
Section 5.3. Added Orenco model AX25-RT3N to approved products list in Table 5-2 (p. 5-16)
Section 4.13. Figure 4.11 replaced due to spelling error (p. 4-46)
Section 4.25. Figure 4.26 replaced due to spelling error (p. 4-86)
Section 5.2. New 4180 gallon septic tank added to Oldcastle Precast (p. 5-7)
Section 8.1. ASTM D-3033 removed because it is no longer manufactured (p. 8-16)
February
Updated to reflect DEQ’s style guide for guidance documents. Changes in this document are reflected in section and subsection numbers, table and figure numbers, and page numbers. In addition, sections 2.1.4 Medium Sand Definition, 4.12 Gravelless Trench System, and 4.20.3.5 Pressure Distribution – In-tank Pumps have been updated based on final recommendations by the Technical Guidance Committee from the January 30, 2013 meeting. DEQ encourages users to replace their entire TGM with this update.
2012
Description
December
Section 3.2.4. Correction in second paragraph about moisture content of soil prior to or during excavation (p. 3-7)
October
Section 2.4. Accelerated installation process guidance (pp. 2-10 - 2-10d)
Section 4.25. Extra filter sand installation in the sand mound (pp. 4-76 - 4-81a)
Section 5.10. Acceptable piping material (p. 5-24)
August
Section 8.6. SeptiTech products added to Table 8-1 (p. 8-43)
Section 5.4. Updated list of approved Extended Treatment Package Systems (p. 5-15)
July
Section 3.2.3. Acceptable piping material (pp. 3-5 - 3-6a) 
Section 3.2.4. Square footage limitations for standard gravity flow systems (pp. 3-7 - 3-7a)
Section 4.8. Evapotranspiration and Evapotranspiration Infiltrative Systems (Section replaced, pp. 4-14 - 4-23e)
Section 5.7. Gravelless trench components table (p. 5-18)
Section 5.8. Certified Septic Tank Effluent Filters table (pp. 5-22 - 5.23)
June
Section 5.4. Extended Treatment Package Systems (Device added to Table 5-2, p. 5-15)
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.

Extended Treatment Package System Subcommittee

Next Scheduled Meeting Date

June 27, 2013, 9:15 a.m. - 4:30 p.m.
DEQ State Office
1410 N. Hilton, Boise
Agenda

Meeting Minutes

Technical Guidance Committee

Next Scheduled Meeting Date

July 18, 2013, 9:15 a.m. - 4:30 p.m.
DEQ State Office
1410 N. Hilton, Boise

Meeting Minutes

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

Drainfield to Surface Water Subcommittee

Meeting Minutes


Page Subscription




Staff Contact

On-Site Wastewater Coordinator
Tyler Fortunati R.E.H.S
DEQ State Office
Water Quality Division
1410 N. Hilton
Boise, ID 83706
(208) 373-0140
tyler.fortunati@deq.idaho.gov

DEQ Resources

More Information

Individual/Subsurface Sewage Disposal Rules

Related Pages

On-Site Wastewater Systems (Septic Systems)

For Engineers and Developers