Cape Cod has a problem with nitrogen pollution of its embayments and waterways. The solution that Massachusetts began to implement on July 7 may offer some lessons for Pennsylvania practitioners. That is because the Cape Cod problem is a specific instance of a more general environmental issue: the nitrogen in surface waters does not come from a few very large polluters, but instead from distributed on-lot sewage systems on individual properties not one of which is a big deal.

Cape Cod is not densely developed, and a large swath of the Outer Cape is a National Seashore. Historically, there has been no need, and little taste, for developing a public sewer in many of the 15 towns. Most properties depend upon on-lot sewage systems. Those systems are blamed for increases in nitrogen concentrations in the freshwater ponds left from the last glaciation and in certain of the embayments of both the Atlantic Ocean and Cape Cod Bay. The wastewater from those on-lot systems ultimately percolates to a surface water, and the overall process does not remove enough nitrogen.