A Case for Point of Sale Septic Inspections

by Rob Karner, Chair, Leelanau Clean Water

Nature of Septic Failure• Contaminated shoreline water samples from septic

diffuse quickly and are hard to detect

• Septic systems are likely to worsen over time as they age and the finite absorption capacity of the area soils are exhausted (currently a 17-25% state-wide failure rate)

• Septic system aging is directly proportional to the amount of use

• Currently, once a septic system is installed, there is no mandatory follow-up evaluation

Some Causes of Septic Failure

• Root intrusion from trees/shrubs

• Hydraulic overload

• Undersized systems

• Soil clogging

• Broken pipes, grease build up, and failure to pump tanks

Natural Aging of Lakes• All lakes age over time

• Lakes that are new have low phosphorus and nitrogen levels

• Lakes that are “old” have high nutrient levels

• The aging process is normal

• The speed of aging due to septic influences is not normal

Ground Water Flow• Ground water typically moves

• The speed of ground water flow depends on soil type and gradient of sloping land

• Ground water can carry nutrients into spring fed lakes

• Septic drain fields can leach nutrients into ground water

Influences of Surface Water Flow

• Rivers, Creeks, Brooks, and Springs carry surface water (downhill) into lakes

• Run off from rain/snow melt can carry nutrients into lakes from failed septic systems

• Surface water flow from failed septic systems can also add human pathogens (E.coli) to lake waters

Influences of local soil types• Sandy soils are both a blessing and a curse

• Sandy soils drain fast and can carry nutrients into the ground water and reduce or eliminate runoff of surface water (Blessing)

• Without a greenbelt (deep rooted native plants), sandy soils can easily load up with nutrients (Curse)

• Sandy soils can build up nutrient loads and release them in high quantities if the septic system is overloaded

Green Belt Influences• Green belts (or natural shorelines) can remove

nutrients from soils before they get carried to the lake by ground water flow

• The current trend is riparian’s are reducing or eliminating green belts putting more nutrient loading pressure on lakes

• The more green belts filter out nutrients with deep rooted plants and convert nutrients into plant matter, the cleaner the lake

Nutrient Loading - A One Way Street

• As nutrients build up in the lake there is very little transport of those nutrients out of the lake via outlets

• Nutrient accumulation (build up over time) in lake bottoms can speed up the aging process if the source of those nutrients are from human origin (septic)

• Nutrients can be in different chemical forms that either make them available to the biota or they can be bonded (sequestered) in the sediments and are not available to the biota

Influences of Climate Change

• Lakes with excess accumulation of nutrients tend to release the sequestered phosphorus under zero oxygen conditions

• Warmer temperatures that are now extending longer into the fall will increase the available phosphorus

• More available phosphorus will stimulate aquatic plant growth that will live and die and decompose

Educational Influences• Education is a key tool in preventing septic

failure

• Well maintained septics last longer

• Thanks to lake associations and some townships, education can be an effect tool in preventing septic failure and promote longer lasting septic systems

Population Growth Influences

• Current trend is to take “inherited” lakefront property and use it as short term rental

• Short term rentals can create more strain on septics with extra guests that can overload septic systems

• Trends of properties being used year round vs. seasonal

• Visitors tend to be from cities with sewer systems and have little or no knowledge about abusing septic systems

New Septic Monitoring Tools on the Horizon

• Within a year, standard, EPA approved enteric bacteria (human) will be employed to measure septic failure

• Leelanau County will likely be a “test site” for septic failure protocols

• qPCR (human bacteria counting) will be able to give fast and reliable results in two hours and will likely be a part of the new septic monitoring programs that will help evaluate septic inspection progress over time