Suffolk County says new septic systems are working to filter out nitrogen in the local water supply.
The East Hampton Star reports that the combined use of these low-nitrogen septic systems has drastically cut down the levels of nitrogen in the water.
The county has been encouraging the adoption of these systems by offering rebates for new installations. About 550 systems have been installed so far.
Excessive nitrogen in the water is a pollutant that can cause harmful algal blooms, fish kills and other environmental problems.
County officials say that the average nitrogen output of all the systems is 17.5 milligrams per liter, with some measuring lower. Older systems would hit an average of 65 milligrams per liter.