Despite Growing Risks, Coastal States Are Underinvesting in Septic System Resilience

A new working paper and report show that states are not prioritizing data collection and funding strategies that benefit septic infrastructure.

Date

April 1, 2026

News Type

Press Release

What's the story?

Septic systems damaged by floods and groundwater inundations can pollute ecosystems and harm human health. As sea level rise intensifies along the Atlantic and Gulf Coasts, these risks will only become more pronounced in coastal communities that largely rely on septic for wastewater management.

A new working paper and report coauthored by scholars from Resources for the Future (RFF) show that states are not prioritizing data collection and funding strategies that benefit septic infrastructure. While public sewer as an alternative to septic is valuable, as reflected in house prices, it can lead to more development in high flood risk areas. Sewer access in coastal Maryland drives up housing values and spurs development, leading to 30 percent higher property values on a per-acre basis. Over the next decade, these growth impacts could place $60.5 million more in assets at risk of sea level rise.

Overall, the analyses point to the need for states to lay the groundwork for policies that keep safe those reliant on septic, while also dissuading further development of homes and businesses in at-risk areas.

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Expert Perspective

Is sewer the solution?

While expanding and connecting homes to sewer is likely to reduce climate-driven health hazards, such moves can be costly and increase the number of people and assets harmed by coastal flooding. The new RFF working paper finds evidence of this in coastal Maryland, where rates of sea level rise are more than twice the global average and 24 percent of homes rely on septic systems.

The paper shows that properties with sewer access are more valuable than those on septic, reflecting consumer preference for sewer access and the denser development that sewer enables. This shows that providing sewer to homes currently on septic would be valuable. However, sewer access spurs development: the number of developed residential parcels increases 1.5 percent faster per year in places with sewer access compared to parcels without access. This suggests that care needs to be taken in places where sewer is provided so as not to put more assets at risk.

The study found that planned sewer expansions in Maryland are likely to increase the number and value of residential properties at risk of sea level rise. In ten years' time, an additional $60.5 million would be exposed to sea level rise, an increase of 50 percent above current levels.

How are public programs helping those on septic?

According to the RFF report, most states are devoting little funding to septic resilience. The largest available source of funding for states, the Clean Water State Revolving Fund, is supported by grants from the US Environmental Protection Agency and is typically not used for septic improvements. Of the 19 Gulf and Atlantic states included in the analysis, 16 devoted less than 3 percent of the fund to septic projects and improvements in the most recent fiscal year. Delaware, Florida, and Georgia committed more, and Delaware spent 24 percent of its fund allotment on sewer expansion in septic-dependent areas. Florida, Maryland, Massachusetts, and New York have their own state funding programs for septic systems, which are mostly used for system upgrades rather than conversion of septic properties to sewer.

The authors argue that this lack of funding prioritization stems in part from a gap in knowledge about septic systems: most states are not collecting data on septic system locations, ages, and conditions, nor are they considering how sea level rise could impact septic systems. Only Virginia acknowledges the impacts of sea level rise on septic systems, although state regulations that would put that knowledge into practice have not been finalized.

Expert Perspective

Where can I learn more?

For more on sewer access and development trajectories, read the working paper "Sea Level Rise and Coastal Infrastructure: The Tradeoff Between Protection and Exposure" by RFF scholars Yanjun (Penny) Liao, Margaret Walls, and Emma DeAngeli.

For more on state and local funding for septic upgrades and data collection strategies, read the report Adapting Wastewater Infrastructure to Sea Level Rise: A Review of Coastal State Policies for Septic Systems by DeAngeli, Walls, and Stanford University visiting student researcher and former RFF intern Yongfan Zhao.

Resources for the Future (RFF) is an independent, nonprofit research institution in Washington, DC. Its mission is to improve environmental, energy, and natural resource decisions through impartial economic research and policy engagement. RFF is committed to being the most widely trusted source of research insights and policy solutions leading to a healthy environment and a thriving economy.

Unless otherwise stated, the views expressed here are those of the individual authors and may differ from those of other RFF experts, its officers, or its directors. RFF does not take positions on specific legislative proposals.

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