How to install a septic tank in Idaho

How Do I Install A Septic System in Idaho? A Step-By-Step Guide

By: fitzgerald Comments: 0

Idaho is growing rapidly, especially in urban areas like Boise, Meridian, Nampa and Caldwell. But it’s also experiencing rapid growth in the more rural areas including Kuna, Marsing, Emmett and beyond. 

Many homeowners are looking at building locations where municipal city services like water and sewage are not available, and that means they are looking at having septic tank systems installed. 

But what is the process for having a septic system approved and installed in Idaho?  We have created this handy guide to help you understand the process and make sure that you avoid common pitfalls, setbacks, and unpleasant surprises along the way.

The Approval Process. 

Having a septic system installed requires a lot more forethought, planning, and approval than many may initially think when they are purchasing a property, or when they are having a home built. 

But don’t let that overwhelm you! We are here to help every step of the way, and ensure that the process goes as smoothly as possible. So what’s the process, and how do you navigate it successfully?

This information is intended to aid you in the application process, by providing you with information on how you can successfully apply for a septic permit with the Southwest District Health Department, obtain the permit, and meet installation requirements. Southwest District Health serves Adams, Canyon, Gem, Owyhee, Payette and Washington counties.  If you’re in Ada, Valley, Elmore or Boise county, please refer to Central District Health’s process for septic system applications.  The process is similar, but may vary slightly from this information.

  1. Obtain a septic permit application either on-line or at any Southwest District Health (SWDH) office.  Applications must be complete and include a zoning certificate, parcel number, and a detailed plot plan  The appropriate fees must be submitted at this time.
  2. Schedule a test hole with the Environmental Health Specialist (EHS) at least 48 hours prior.  Applicant and/or installer MUST be on-site during the site evaluation.
  • Test holes must be excavated while the EHS is present.  The drain field must be placed within 50 feet of the test hole.  The permit will be issued or denied within three (3) working days.  Permits can be picked up, mailed, or sent via facsimile. Note: Southwest 
  • District Health may require soil analysis, groundwater monitoring, trench inspections, engineering or maintenance agreements for complex alternative systems or as specified on any particular lot where appropriate. 
  1. All subsurface sewage disposal systems must be inspected prior to covering, (Prior 48-hour notification is required).  
  • Installers MUST be on-site during the final inspection(s).  Gravel/sand receipts may be requested. A list of approved gravel products may be obtained through SWDH.  
  • Systems where construction is not completely finished, installer not present, etc. will not be finalized and must remain uncovered until finalized. 

Note: Additional inspections may be required for complex alternative systems or on standard systems when required by EHS staff. 

By going through this process correctly, you can avoid expensive delays, setbacks, and nasty surprises that can cost you time, money, and delay or prevent the successful installation of your septic system.

Homeowner Checklist

Looking for more details on the process? Here is a detailed checklist and breakdown of the steps needed in order to be approved. 


Required Inspections: 

  • Test hole/site evaluation
  • Trench Inspection (trenches excavated, no gravel or pipe in trench, just the bare trench)
  • Final Inspection (everything is done but system is not covered) 

Set Backs:

  • Drain field 50 feet from all temporary surface water (irrigation ditches, canals, etc.) 
  • Drain field 100, 200 or 300 feet from surface water*
  • Drain field 100 feet from well
  • Drain field 10 feet from the foundation or 20 feet from the basement
  • Septic tank 50 feet from well
  • Septic tank 50 feet from permanent surface water
  • Septic tank 5 feet from the foundation 
  • Septic tank and drain field 6 feet apart
  • Drain field 5 feet from the property line 
  • Designated replacement area for drain field that can also meet the above setbacks  

Need Help or Have Questions? 

If you have questions about your property, plot plan or plans for having a septic system installed, give us a call ( 208) 340-4691or email us at heather@fitzgeraldmechanical.com

Handy Numbers and Website:





Website: www.phd3.idaho.gov


Sources: Southwest District Health Department

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