When Climate Change Really Stinks: Septic Impacts

What does climate change mean for your toilet? A new report from the International Panel on Climate Change has policymakers and journalists from around the world scrambling to decode the impacts of rising sea levels and growing storms. Among potential casualties: the venerable New England institution of the flushing toilet.

Around 55 percent of Vermont households rely on septic systems for waste treatment – that’s the highest level in the country – and about 50 percent of the homes in New Hampshire and Maine fall into the same category. But climate change threatens to make these systems obsolete, and to understand why, it’s necessary to understand how a septic system works.

Most septic systems come in three parts: a toilet, a tank, and a field. When you flush, the stuff in the toilet flows into the tank, where the solid material separates from the water. Then the water flows into a field, where remaining impurities are broken down naturally. Or that’s how it’s supposed to work.

If the field becomes totally saturated, either by spring slush or a fall flood, the system reverses itself. Water flows back from the field into the tank, and can back up all the way into your house, potentially causing tens of thousands of dollars in damage, not to mention odor, inconvenience, and health risks.

Though insulated from the impacts of warming oceans and rising seas, Vermonters have historically congregated along the state’s rivers and valleys, and they’re not totally beyond the reach of oceanic weather influences. In 2011, Hurricane Irene dumped up to 11 inches of water on Vermont, and caused $13.5 billion in damage across the U.S. That was bad enough, but over the next century, the Green Mountains stand to become a lot wetter.

Congress anticipates that as New England warms up, it will shift from a “cold, snowy winter” to a “warm, slushy” one. Goodbye, skiing, and goodbye, fall foliage. But solid waste is a less-popular topic of discussion. The 2018 National Climate Assessment predicts increased spring and fall rainfall across New England. Deforestation, as might result from climate change, can also lead to a rising water table. Together with the predictions of the IPCC report, these documents paint a bleak scenario for sanitation.

The IPCC predicts not only an increase in hurricanes, but an amplification of their severity, precipitation, and potentially their northerly range. It also forecasts an increase in extreme weather patterns, such as El Niño and the notably wet La Niña. More threats loom along New England’s 473-mile coastline, where rising seas (exceeding the global average) may be accompanied by more extreme wave heights and tidal events, raising the coastal water table. All these factors threaten to multiply floods.

Floods, in turn, multiply septic failures. A study in Connecticut found that just one inch of rainfall could significantly increase the likelihood of developing a stomach illness after swimming (see the National Climate Assessment), a finding consistent with the possibility of septic contamination.

Last year, the Conservation Law Foundation issued a report examining the effects of climate change on New England’s septic systems, and on the potential public-health impact of their failure.

“New England states are not adequately addressing rising groundwater and other climate change impacts when regulating the location, operation, or inspection of septic systems,” the report concluded. “Residents may not see the effluent, but they will smell it.” New England’s coastal states will be hardest-hit, but Vermont “is still expected to experience an increase in extreme precipitation events, flooding, increased rises in temperatures, and erosion, which could have serious consequences on infrastructure like septic systems.”

For now, the atlas at Flood Ready Vermont can show Vermonters whether their homes lie on a marked floodplain, and the EPA provides guidelines on handling a flooded septic tank.


Around the U.S., septic systems have generally declined in popularity, but in New England they continue to be installed with many new homes. Infographic courtesy of CircleofBlue.org

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