Septic regulations and suburban development patterns : an analysis based on soil data in Norfolk County, Massachusetts

Abstract

Urban sanitation systems are fundamental elements of modern urban development. Decentralized, privately operated, on-site wastewater disposal systems have also played an important role in suburban and exurban development over the past fifty years. This research is an attempt to assess the current influence of on-site wastewater disposal technology and regulations on land use patterns in Norfolk County, Massachusetts; to estimate the potential impacts of technological and regulatory change; and to assess the potential role of on-site sanitation policies in managing suburban and exurban development. I grouped soil types into seven interpretive classes based on their limitations for wastewater disposal; and created a Soil Development Index, which represents the relative proportion of soil classes in available and developed land over time. I found that soils with high groundwater and slow permeability are systematically underrepresented in residential development utilizing on-site wastewater disposal; comparisons to sewer service areas suggest these patterns may be due to regulatory restrictions on the use of septic systems. Slowly permeable soils and shallow bedrock areas are also associated with larger lot sizes in unsewered areas. The land-consumptive patterns of development observed in unsewered suburbs suggest that the current system of on-site sanitation is closely linked to other public policies that promote large-lot single family large-lot development to the exclusion of more diverse development models. The history of centralized and decentralized sanitation systems in the United States demonstrates that sanitation policies have evolved over time to address a wider variety of social and political concerns, including explicit planning objectives. Additional research is necessary to assess how sanitation policies -- including standards for on-site wastewater disposal -- might be used as implementation mechanisms for land use and planning policies intended to promote sustainability