OUR GEM: Protecting our greatest resource

One of the greatest treasures North Idaho has to offer is the abundance of surface water and groundwater. As our area continues to develop, effectively managing impacts of wastewater disposal to this precious resource is becoming increasingly important. Although our area boasts some of the most advanced municipal wastewater treatment facilities in the Northwest, many properties throughout North Idaho rely on subsurface septic systems to treat and dispose of wastewater and will likely never be connected to a centralized system. Septic systems play an important role in wastewater disposal because they balance both the treatment (removal of nutrients and pathogens) and disposal (wastewater does not surface or back up) of wastewater on an individual property basis.

As one of seven Health Districts in Idaho, Panhandle Health District manages subsurface sewage disposal in the five northern counties of Idaho. Annually, Panhandle Health District issues more septic permits than any other health district in Idaho (approximately 25% of total permits and 33% of complex permits issued statewide), with approximately 1,500 new systems installed in 2022. Permitting of septic systems is a collaboration between the individual Health Districts, Idaho Department of Environmental Quality, county building and planning departments and individual property owners. They are regulated by the Idaho Rules for Individual/Subsurface Sewage Disposal and the Idaho Technical Guidance Manual for Individual and Subsurface Sewage Disposal Systems. Every septic system is designed and permitted based on specific parameters that include the proposed use of the system, and unique site characteristics in North Idaho represent many challenges for subsurface sewage disposal due to the prevalence of surface and groundwater, diverse geology, and amount of precipitation. Idaho is proactive in adopting new wastewater disposal technologies and implementing these technologies to facilitate growth in challenging areas while minimizing impacts to the environment.

The Idaho Rules protect groundwater by requiring treatment of effluent to remove nutrients and pathogens before contact with groundwater, and protect surface water by requiring setbacks between septic system components and surface water. If an area does not have adequate soil to treat effluent, alternative systems can be used to provide additional treatment. In relation to surface water protection, Idaho has the largest setback requirement between drainfields and surface water of any state in the U.S., and can require drain fields to be as far as 300 feet from surface water. None of the alternative systems currently available on an individual basis are effective at removing phosphorus, the main nutrient of concern for surface water, so the rules do not allow alternative systems to be used for reduced setbacks to surface water.

While the Idaho rules do not account for the cumulative impact to ground and surface water from high-density individual septic systems. There are numerous examples of contaminated aquifers and bodies of water throughout Idaho that can be attributed to high density septic systems, and it will become increasingly important to keep this aspect of wastewater disposal in mind as our area continues to develop. This issue is especially important along Lake Coeur d'Alene due to the sheer number, age and dimensions of waterfront parcels. The Idaho Rules for septic systems were adopted in 1973, and any use prior to this are grandfathered. Many of the parcels along the lake were created prior to 1973 and the homes on these parcels continue to use the original, antiquated systems. The dimensions of many of the existing parcels do not allow for minimum surface water setbacks or fully sized septic systems. Panhandle Health District works closely with property owners to upgrade these systems to the best possible standards on each parcel, but site conditions do not always allow for installation of systems that are protective of water quality.

There are many things the public can do to minimize impacts of septic systems including:

• Inspect your septic system annually for signs of failure
• Pump septic tanks before scum levels reach 40%
• Get to know your septic system and how it functions so the area can be protected
• Preserve replacement area on your property to allow for a replacement system if your drainfield
• Work with Panhandle Health District to upgrade your system if the existing system is not functioning properly or pre-dates the rules
• Evaluate existing septic systems prior to purchasing properties and upgrade antiquated systems as part of the real estate transaction

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The Our Gem Coeur d’Alene Lake Collaborative is a team of committed and passionate professionals working to preserve lake health and protect water quality by promoting community awareness of local water resources through education, outreach and stewardship. Our Gem includes local experts from the University of Idaho Community Water Resource Center, Coeur d’Alene Tribe, Idaho Department of Environmental Quality, Kootenai Environmental Alliance, Coeur d’Alene Regional Chamber of Commerce, Kootenai County and CDA 2030.

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Jason Peppin is an environmental health specialist with Panhandle Health District.