Watch the lecture video of “Water Resource Planning in Suburban Landscapes with Private Wells and Septic Systems: Better Understanding Spatial Risk to Protect Human and Environmental Health” presentation by Bradley T. Vowels, PhD Candidate, Lecturer, Department of Planning and Landscape Architecture, UW-Madison

Lecture Summary

Septic systems are designed to collect, treat, and release household effluent into the groundwater. If these decentralized systems are not properly installed, regularly maintained or are spatially distributed at densities that exceed the landscape’s ability to safely treat wastewater effluent, groundwater can become contaminated. According to the U.S. EPA, failing septic systems are the second greatest threat to groundwater quality. Groundwater contamination is a potential health risk for suburban households that rely on private wells to supply their drinking-water. Contamination risks are higher for homes in landscapes with vulnerable hydrogeologic conditions, intensive agriculture, and clustered septic systems. Wisconsin’s plumbing code allows households to be served by private wells and on-site septic systems. Land-use policy now allows clustered housing development on suburban sites that were once considered unsuitable for septic systems due to environmental constraints. Such clusters can create “hot spots” of groundwater contamination. More frequent well monitoring and septic system maintenance can help households protect their drinking water. For local governments, geospatial analyses of existing septic systems and land suitability can ensure that future septic systems minimize risks to the environment and human health. In this presentation, I will explore state and local septic system regulations and the spatial distribution of septic systems within the Southeastern Wisconsin Regional Planning Commission (SEWRPC) area over the past 50 years. This research has uncovered clusters of septic systems and private wells that warrant additional investigation and groundwater monitoring that could help protect human and environmental health. This method of analysis can help public-sector planners develop and implement more context sensitive policy responses to unsewered suburban housing developments in vulnerable landscapes.

Related Publications:
LaGro, Jr., James A. & Vowels, Bradley T. (2019). How Dense Should Septic Systems Be? Managing Risks from Clustered Septic Systems. In Nelson Issue Brief: Nitrate Contamination in Groundwater.
LaGro, Jr., James A., Vowels, Bradley T., & Vondra, Benjamin (2017). Exurban Housing Development, Onsite Wastewater Disposal, and Groundwater Vulnerability within a changing policy context. Landscape and Urban Planning, 167, 60-71.