Big questions, local data

Big questions, local data: Capps lab member and M.S. student Kyle Connelly interns with the Athens-Clarke County Public Utilities Department to help build a geodatabase to answer questions about septic systems

Over 26 million housing units in the U.S. rely on onsite wastewater treatment systems (OWTS’s or septic systems)[1], and about 16% of new homes in the Southern U.S. were installed with private OWTS’s in 2019[2].  Though we trust these systems (new and old alike) to be operating effectively, very little is known about actual private septic system performance.  It is likely that issues arise as OWTS’s age or if they are improperly installed or maintained.  Athens-Clarke County has nearly 10,000 OWTS’s in its jurisdiction, many of which are approaching the end of their recommended service life (about 30 years[3],[4]).  Relatedly, environmental managers would like to better understand where pockets of problematic OWTS’s are located in order to make decisions about future land development and wastewater treatment plant service area expansion.  To address these gaps in knowledge, the County Public Utilities Department, in conjunction with the Geospatial Information Office, has invested substantial time and effort over several years to build and verify a geodatabase of registered OWTS locations in Athens-Clarke County.


Kyle joined this project in January of 2020.  Since then, he has been working with Public Utilities Department personnel to enter OSWT pumping data for each tank.  This project is only possible because the County had the foresight to keep records of where, when, and how much volume septic trucks had pumped in Athens-Clarke County over the last five years.  As one may expect a normally functioning private OSWT unit to be pumped approximately every 3-5 years, by adding this data to the OSWT system locations map, Athens-Clarke County will be able to more accurately identify systems which are likely failing if pumping frequencies exceed this level.  Likewise, Kyle will analyze the age and siting characteristics of OSWT’s to determine if age or environmental drivers are better predictors of anomalous tank pumping frequencies.  These additional analyses will help the County decide where to invest in wastewater treatment infrastructure projects in the future.

[1]U.S. Environmental Protection Agency. 2008. Septic Systems Fact Sheet. Office of Wastewater Management # 832-F-08-057. Washington, D.C.

[2] U.S. Census Bureau. 2020. Characteristics of New Housing: Type of Sewage System by Water Supply Source in New Single-Family Houses Completed. Residential Construction Branch. Washington, D.C.

[3] Winneberger, J. T. 1975. Sanitary Surveys and Survival Curves of Septic Tank Systems. Journal of Environmental Health 38:36–39.

[4] Noss, R. R., and M. Billa. 1988. Septic System Maintenance Management. Journal of Urban Planning and Development 114:73–90.