Why septic tanks have become such a big problem on Cape Cod compared to the rest of Mass.
February 12, 2024
Nik DeCosta-Klipa
WBUR

A super (toilet) bowl problem: Cape Cod’s water — its coastline, its freshwater ponds, its saltwater bays — is the linchpin of its tourism-centric economy, and it’s increasingly in bad shape. A recent report found 90% of Cape Cod’s coastal bays and more than a third of its ponds — used for swimming, boating and fishing — now have “unacceptable” water quality. There are solutions to this problem. But as WBUR’s Barbara Moran reports in this new two-part collaboration with Scientific American, they’re not cheap. Last year, as Barb first reported, the state issued new rules that could require Cape towns and property owners to fork up huge sums of money to upgrade their septic systems in the coming years. But why aren’t the rules needed in other parts of Massachusetts? Before we dive in deeper, here’s a look at what makes this problem unique to our favorite peninsula:

• Inside the septic tank: To understand the Cape’s problems, you need to understand the humble septic tank. About 85% of Cape Cod properties use septic tanks, rather than a connected sewer system. That means all of the houses’ wastewater (from the toilet, the sink, etc.) flows into a large underground tank. The solids sink to the bottom of the tank, while the untreated liquid — rich in algae-feeding nutrients – seeps into the ground.
• Why are septic tanks a problem? Septic tanks are fine in rural areas where houses are spread out. But that’s no longer the case for much of the Cape. The region’s population has nearly quintupled since the 1950s — from 50,000 full-time residents to 230,000 today. And that doesn’t count the millions of visitors that flock there each summer. In other words, the Cape has simply gotten too dense to absorb all that wastewater.
• There are two other environmental factors: The Cape’s sandy soil makes it extra-easy for that liquid to flow into bays and ponds. Meanwhile, climate change makes algae blooms grow faster.
• What are the solutions? Barb’s story has a closer look at how different Cape communities are approaching the issue. Generally, there are two approaches. The first is switching more populated towns onto sewer systems — a long, complicated and expensive process. The second is upgrading your septic system (less time-consuming, but individually expensive).
• There’s also a third, relatively cheaper solution — which involves a special toilet. You can read more about the promise of “pee-cycling” in the second installment of Barb’s series.

Why septic tanks have become such a big problem on Cape Cod compared to the rest of Mass. – WBUR