Evaluating Statewide Wastewater Affordability for Users of Sewer Systems and Onsite Wastewater Treatment Systems Based on Household Incomes at the Census Tract Level.

Wastewater affordability is a pressing concern in the US as the cost of collecting and treating wastewater continues to rise rapidly, and reports have revealed that millions of residents are experiencing a lack of equitable access to affordable wastewater management. The USEPA has established an affordability metric based on 2.5% of median household income (MHI) and affordability is typically interpreted as the monthly utility bill. However, this approach is not applicable to the 25% of US households that are not connected to networked sewer. This study developed the first statewide methodology for mapping wastewater affordability for users of both networked and onsite wastewater treatment systems (OWTS) based on USEPA guidelines. The methodology used local data from the Alabama Department of Environmental Management (ADEM), utilities, and the US Census Bureau. This article presents a novel methodology for quantifying water and wastewater affordability challenges for large geographical areas while maintaining the accuracy of small-spatial scale analysis. This study also incorporated income inequalities by using census tract-level household income data to estimate the number of households in Alabama with unaffordable wastewater access. This study revealed that wastewater access affordability challenges are more widespread than indicated by traditional MHI-based analysis and are likely affecting approximately 445,000 households in Alabama (23.7%). This study also showed that expansions in the available funding and types of eligible applicants for grant programs that subsidize OWTS capital costs could reduce OWTS affordability challenges eightfold. We propose using this methodology to quantify affordability challenges alongside a suite of approaches to address wastewater affordability in the US at the utility and household levels to preserve the human right to affordable sanitation. Practical Applications: Wastewater affordability is a key aspect of providing sustainable wastewater collection and treatment for US residents. The ongoing discussions about wastewater access affordability are often centered around customers of sewer utilities and neglect to consider the affordability challenges of residents with OWTS (commonly known as septic tank systems). This study develops a methodology for analyzing statewide wastewater access affordability for both residents with sewer bills and users of OWTS based on annual household incomes at the census tract level. This study reveals that wastewater affordability challenges affect both users of centralized sewer networks and OWTS including approximately 445,000 households in Alabama (23.7%). [ABSTRACT FROM AUTHOR]