The Big Stink: Climate Change has Septic Systems Backing Up

April 13, 2022

It’s not just roads, bridges and dams that are failing due to climate change.
Our most humble infrastructure is in trouble – very expensive trouble – as well.

Washington Post:

As climate change intensifies, septic failures are emerging as a vexing issue for local governments. For decades, flushing a toilet and making wastewater disappear was a convenience that didn’t warrant a second thought. No longer. From Miami to Minnesota, septic systems are failing, posing threats to clean water, ecosystems and public health.

About 20 percent of U.S. households rely on septic, according to the Environmental Protection Agency. Many systems are clustered in coastal areas that are experiencing relative sea-level rise, including around Boston and New York. Nearly half of New England homes depend on them. Florida hosts 2.6 million systems. Of the 120,000 in Miami-Dade County, more than half of them fail to work properly at some point during the year, helping to fuel deadly algae blooms in Biscayne Bay, home to the nation’s only underwater national park. The cost to convert those systems into a central sewer plant would be more than $4 billion.

The issue is complex, merging common climate themes. Solutions are expensive, beyond the ability of localities to fund them. Permitting standards that were created when rainfall and sea-level rise were relatively constant have become inadequate. Low-income and disadvantaged people who settled in areas with poor soils likely to compromise systems are disproportionately affected. Maintenance requirements are piecemeal nationwide. And while it’s clear that septic failures are increasing, the full scope of the problem remains elusive because data, particularly for the most vulnerable aging systems, are difficult to compile.

“The challenges are going to be immense,” said Scott Pippin, a lawyer and researcher at the University of Georgia’s Institute for Resilient Infrastructure Systems who has studied the problem along the state’s coast. “Conditions are changing. They’re becoming more challenging for the functionality of the systems. In terms of large-scale, complex analysis of the problem, we don’t really have a good picture of that now. But going forward, you can expect that it’s going to become more significant.”

Pippin’s work in Georgia is one of several studies as states from New Hampshire to Alabama confront the effects of septic system failures. Michigan’s Department of Environment, Great Lakes and Energy estimates that 24 percent of the state’s 1.37 million septic systems are failing and contaminating groundwater. A project funded by the National Oceanic and Atmospheric Administration is examining the potential longer-term impacts of climate change on septic systems in the Carolinas. Virginia has created a Wastewater Infrastructure Policy Working Group to address the issue.

An EPA spokesman said the agency didn’t have a report on the septic problem but noted that sea level rise, changing water tables, precipitation changes and increased temperature can cause systems to fail. The infrastructure bill passed last year provides $150 million to replace or repair systems nationwide.

For a century, conventional septic systems have been an inexpensive solution for wastewater. They work by burying a tank that collects wastewater from sinks, toilets, showers and washing machines, holding the solids while the liquid percolates through a few feet of filtering soil, where microbes and other biological processes remove harmful bacteria.

When that doesn’t happen, bacteria and parasites from human waste flow into drinking water supplies or recreational waters, creating a public health problem. Nitrogen and phosphorous, also a byproduct of the waste, pollute waters, creating oxygen-depleted zones in rivers and along the coast, closing shellfish harvests and killing fish.

For decades, septic systems have been designed with the assumption that groundwater levels would remain static. That’s no longer true. “Systems that were permitted 40, 50 years ago and met the criteria at that time now wouldn’t,” said Charles Humphrey, an East Carolina University researcher who studies groundwater dynamics. In North Carolina’s Dare County, which includes Outer Banks destinations such as Nags Head and Rodanthe, groundwater levels are a foot higher than in the 1980s.

That means there’s not enough separation between the septic tank and groundwater to filter pollutants. The threat isn’t only along the coasts. More intense storms dumping inches of rain in a few hours soak the ground inland, compromising systems for weeks. Too little precipitation is a problem as well. The lack of early, insulating snow in the Midwest, attributed to climate change, drives down the frost line, freezing drain fields and causing failures.

Georgia spent years creating a comprehensive database of septic systems, the only state to complete one. “Everybody wants to skip to a solution — how do we build a new infrastructure for the future? But I think the story is really the value of investing in the data and in that preliminary research to make smart investments and wise decisions,” Pippin said.

An EPA spokesman said the agency didn’t have a report on the septic problem but noted that sea level rise, changing water tables, precipitation changes and increased temperature can cause systems to fail. The infrastructure bill passed last year provides $150 million to replace or repair systems nationwide.

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