Bannock County Groundwater

Septic System Toolbox

Septic Tank InstallerSeptic system siting and installation is regulated by Southeastern Idaho Public Health.Bannock County, through zoning ordinance, has elected to limit the size and location of lots where septic systems are allowed in order to minimize contamination to ground water (which is our drinking water).  The primary contaminant of concern is nitrate, which is seen at elevated levels in many private, and some public, wells in Bannock County.



It is your responsibility to maintain your septic system. There are no monitoring or maintenance requirements for standard septic systems. No regulatory agency inspects septic systems after they are installed. Homeowners are solely responsible for using a septic system correctly and for maintaining the system. Neglecting your system can cause it to fail. Failing septic systems are expensive to repair, contaminate groundwater, and cause sewage odors and back-up into your house.

  • Pump your tank every 3-5 years by a licensed septic contractor. Keep a record of this pumping and other maintenance.
  • Divert roof drains and driveway runoff AWAY from the septic system.
  • Practice water conservation to extend the life of your system.
  • Don’t poison your system and groundwater by pouring chemicals down the drain.
  • DON’T drive or park over any part of the system.
  • Keep trees away from the system. Tree roots can clog and damage the drain lines.

Septic Systems and Nitrate


Septic systems leach bacteria and nutrients. Careful consideration of their location relative to wells, ground water and other septic tanks is important for the quality of our drinking water.

Southeastern Idaho Public Health
Regulations and permitting requirements for septic systems in Bannock County, Pocatello, and Chubbuck.

City of Pocatello and City of Chubbuck

New septic tanks are NOT permitted when the property line is within 300’ of an existing sewer line.

What do septic systems do?

Like large waste water treatment facilities, private septic systems treat solid and liquid waste from household toilets, sinks and showers. This treatment consists of allowing sludge and scum to separate from the liquid effluent. The liquid effluent is then released into the ground via a leach field/drain field. This effluent flows into local groundwater. A few basic facts are important to remember:

  • Septic systems only treat organic matter: feces, urine, toilet paper, and the organic matter in wastewater from the kitchen, laundry, and bath.
  • Septic systems release nitrate into the subsurface and into groundwater, even if they are properly designed, constructed, functioning, and maintained.
  • Septic systems do not treat or remove:
    • Pharmaceuticals: including antibiotics, antidepressants, anti-psychotics, endocrine disrupting chemicals, birth control, hormones, beta blockers, steroids, sexual enhancement drugs, over-the-counter drugs
    • Personal care products: cosmetics, fragrances, menstrual care products, lotions, soaps, sunscreen
    • Household cleaning products or other chemicals: pesticides, paints, oils, lawn chemicals, including illicit drugs and associated manufacturing chemicals.
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