Missed signals: Virginia’s septic strategies overlook critical timing, study warns

Missed Signals: Virginia’s Septic Strategies Overlook Critical Timing, Study Warns 

Washington, D.C., December 8, 2025 – A new study from the University of Maryland’s Jerin Tasnim, reveals that Virginia's current approach to managing septic system failures misses a critical factor: the time-varying relationship between hydrological stressors and septic system performance. This gap limits the state's ability to proactively identify and intervene in high-risk areas before failures occur—and before nitrogen pollution reaches the Chesapeake Bay. This study will be presented on December 8 at 10:30 A.M. ET at the Society for Risk Analysis Annual Meeting in Washington D.C. 

 

Septic systems represent a significant source of nutrient pollution to the Bay, particularly in rural areas not served by public sewer. While Virginia's Phase III Watershed Implementation Plan focuses on reducing nitrogen loading through inspections, pump-outs, and system upgrades, current strategies rely on static indicators like system age and proximity to water. These approaches don't capture how septic stress varies over time in response to rainfall, riverine flooding, and tidal inundation. 

 

Tasnim analyzed daily septic maintenance calls from 2011 to 2023 across coastal Virginia's river basins using advanced cross-wavelet coherence analysis—a technique that reveals time-frequency dependencies between environmental stressors and infrastructure responses that conventional statistical methods often miss. 

 

Key Findings: 

Septic issues in Virginia’s coastal river basin do not occur randomly. Instead, they follow strong and consistent patterns that align closely with seasonal rhythms. 

Maintenance cycles peak at six months and at one year, suggesting that outreach support and public education efforts should be timed with these high-volume periods. 

Cycles also varied by basin, suggesting regional targeting may also be most effective. 

Higher water levels, precipitation and tides are closely linked to increased calls, which indicates that local hydrology plays a significant role in determining when problems will arise. 

A large number of calls are from pumping events, meaning that homeowners often wait until problems are already severe. This highlights the need for more proactive and scheduled approaches to reduce system failures that lead to nitrogen pollution.  

Even subtle changes in water conditions can place high stress on septic systems. 

Implications for Policy and Equity: 

“This research offers a pathway to improve how Virginia Department of Health prioritizes interventions under the Chesapeake Bay Watershed Implementation Plan. Integrating time-frequency signals can improve equity by identifying frequently stressed systems in underserved or unsewered communities that may not meet conventional high-risk criteria but experience recurrent hydro-induced failures,” remarked Tasnim. 

By anticipating when problems are most likely to occur, Virginia can send time septic maintenance reminders and assistance more effectively saving families from costly emergency repairs while protecting public health and water quality.  

The findings also suggest that assistance programs should be adapted to account for future climate change impacts and how hydroclimatic hazards will intensify spatially and temporally across vulnerable communities. 

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About Society for Risk Analysis 

The Society for Risk Analysis (SRA) is a multidisciplinary, global organization dedicated to advancing the science and practice of risk analysis. Founded in 1980, SRA brings together researchers, practitioners, and policymakers from diverse fields including engineering, public health, environmental science, economics, and decision theory. The Society fosters collaboration and communication on risk assessment, management, and communication to inform decision-making and protect public well-being. SRA supports a wide range of scholarly activities, publications, and conferences. Learn more at www.sra.org. 

EDITORS NOTE:  

This research will be presented on December 8 at 10:30 EST at the Society for Risk Analysis (SRA) Annual Conference at the Downtown Westin Hotel in Washington, D.C. SRA Annual Conference welcomes press attendance. Please contact Emma Scott at emma@bigvoicecomm.com to register. 

Media Contact: 

Emma Scott 

Media Relations Specialist 

Emma@bigvoicecomm.com 

(740)632-0965 

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