Why is high groundwater a concern for septic systems?

High groundwater levels are a significant concern for septic systems primarily because they can lead to flooding of the drain field and result in system failure. When the groundwater rises close to the surface, it saturates the soil surrounding the septic system and can overwhelm the drain field. This saturation prevents the proper percolation of effluent into the soil, which is essential for the treatment of wastewater.

When the drain field becomes flooded, effluent cannot adequately infiltrate, leading to backups in the system, potential surface discharge, and ultimately, a failure of the septic system. This can create sanitary hazards and environmental issues, including the uncontrolled release of untreated wastewater into the surrounding area.

While high groundwater can pose risks of contaminating drinking water sources as well, the primary issue stems from the inability of the septic system to function correctly when flooded, which highlights the importance of proper site evaluations before installing a septic system in areas where groundwater levels may be high. Proper absorption of effluent, which is crucial for treatment, is significantly hampered by high levels of groundwater, making it a fundamental concern for system design and installation.