Nitrogen pollution from cesspools and septic systems has been identified as the largest single cause of degraded water quality contributing to beach closures, restrictions on shell fishing, toxic algae blooms, and massive fish kills. The new nitrogen reducing septic systems are called I/A systems. "I/A" is an abbreviation for Innovative and Alternative Onsite Wastewater Treatment Systems. These new systems drastically reduce the harmful nitrogen that is affecting our ground water and bays.