SAVING CAPEU, COD'S WATERS: CLF is fighting to clean up the Cape's ailing waters before nitrogen pollution pushes them past the point of no return.

Imagine the kind of summer day we New Englanders wait for all year--a light breeze, an azure sky, temps in the low 80s, and, best of all, low humidity. Coolers are stuffed with snacks and sandwiches, beach chairs stacked in trunks, and kids corralled into waiting cars for the traffic-jammed ride to their favorite Cape Cod beach, where the water has warmed just enough to entice even the least hardy among us.

Such a day is the stuff of cherished summer memories and Cape Cod tourism brochures. But there's an ugly catch to this idyllic scene: The Cape's saltwater bays are in crisis, their water quality degraded severely by excess nitrogen from wastewater. The region's septic systems--which serve 85 percent of households--aren't designed to eliminate nitrogen, which moves through the Cape's uniquely porous soil and seeps into local waters.

"Nitrogen acts like a fertilizer, causing massive algae outbreaks, including bluegreen algae, that float on the water's surface," says Christopher Kilian, CLF Director of Strategic Litigation. The outbreaks can sicken people, plants, and animals and make the Cape's bay beaches and freshwater ponds unsafe for swimming, boating, and shellfishing. Beach closures due to algae outbreaks and high bacteria levels have become an all-too-frequent in recent years, while local swimming holes long beloved by year-round and summer residents alike are today often off-limits to their children and grandchildren.

Nitrogen pollution on the Cape is hardly a secret, says Kilian. Scientific reports show it has been getting worse year after year for decades now. The solution is also well known: Fix the region's septic and wastewater treatment systems, and do it now.

The consequences of inaction are pretty well accepted, too: Beyond the devastating impacts to plants, fish, and wildlife, the growing "brown-slime" economy (a term coined by the region's chamber of commerce) could overpower the Cape's tourism economy and the millions of dollars it pumps into the region every year. After all, it's New England, and beach lovers could easily choose to visit one of the region's other coastal areas where the waters are clean. If the tourists go, so do the summer jobs, retail and restaurant sales, rentals, and all the ancillary businesses that depend on them--along with housing values in both the seasonal and year-round markets.

But there is good news. Thanks to a lawsuit filed by CLF against the Environmental Protection Agency [EPA], in 2015 the Cape Cod Commission updated a 30-year-old Areawide Wastewater Management Plan called a Section 208 plan for the statute in the federal Clean Water Act that mandates it [see sidebar, page 5]. The updated plan outlines the legally...