According to the EPA, more than 26 million households in the U.S. rely on septic systems to treat their wastewater. That’s more than one in five. Septic systems are most prevalent in New England, but they’re also pretty common in the southeast and northwest. And there's a reason for that: they’re a relatively low cost option for small communities. But, in places like Cape Cod, it’s become obvious that there are some major drawbacks, like excess nitrogen flowing from septic systems into nearby