Cape Cod Water Quality Threatened by Septic Runoff

Pollutants from local septic tanks are creating problematic algae blooms in local waters. Cleaning it all up could cost billions.

1 minute read

February 14, 2024, 6:00 AM PST

By Diana Ionescu @aworkoffiction


Close-up of bright green algae bloom on water surface with persons hand reaching in to take a sample in a clear plastic water bottle.

rospoint / Adobe Stock

Toxic algae blooms are threatening the Cape Cod ecosystem and the health of local residents, reports Barbara Moran for WBUR.

In fact, “90% of Cape Cod's coastal bays and more than a third of its ponds have ‘unacceptable’ water quality, according to the nonprofit Association to Preserve Cape Cod's annual State of the Waters report.”

The source of the pollution is mainly local septic systems that leach nitrogen and phosphorus into the groundwater. “About 85% of Cape Cod properties use septic systems to manage household waste, and experts say the technology is not up to the job.” New state regulations charge cities with cleaning this up and installing citywide sewer systems, but the cost will reach into the billions. “The town of Orleans, for example, is building a new treatment plant for about $34 million and expanding sewer lines for millions of dollars more.”

Some homeowners are taking matters into their own hands and installing upgraded septic systems that treat waste at the source, but these, too, come at a high cost and do not filter all harmful contaminants.

Monday, February 12, 2024 in WBUR

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