Combined Sewer Overflows in the Boston Area At the turn of the century, Boston had one of the most advanced sewer systems in the country. Through decades of neglect and a failure to truly update the system until the 1980's, the pollution in Boston Harbor became so bad that the harbor became a national embarrassment. The two sewer treatment plants in Boston Harbor were only equipped for primary treatment when most plants in the country were providing secondary if not tertiary treatment for their waste water. The waste from these plants was being dumped into the shallow waters of the Harbor, at the end of a relatively short outfall pipe. An