For more than a decade, nitrogen pollution has degraded the water quality in Popponesset Bay while the Town of Mashpee has continued to permit hundreds of septic systems that are the known source of the pollution. In a report published earlier this month titled âCape Codâs Polluted Bays: A Decade of Missed Opportunities,â the Conservation Law Foundation counts 648 polluting systems within the Popponesset Bay watershed that have passed inspection or received a permit in the past five to 10 years. Those 648 septic systems fall within the Town of Mashpee and the Town of Barnstable. The CLF in September announced plans to sue both towns and the Massachusetts Department of Environmental Protection to halt septic system installations and inspections.