Answer: Yes, the combined New York and Connecticut total trade-equalized point source average daily load for 2025 was 18,909 lbs/day which is 3,866 lbs/day below the Total Maximum Daily Load (TMDL) target. This represents a 68 percent reduction from the 1990 baseline, the starting point when New York, Connecticut, and EPA agreed to try to prevent increases of nitrogen discharges into the Sound from wastewater treatment plants. The 68 percent reduction indicates that point source nutrient loads are being reduced from wastewater treatment plants, thereby improving water quality.
Nitrogen loading from wastewater treatment facilities is reported by wastewater treatment facilities to the states of Connecticut and New York. The nitrogen loading reported to Connecticut and New York is called trade-equalized loads – with a National Pollutant Discharge Elimination System permit, wastewater treatment facilities can enter a water quality trading program where the facilities can do other actions to improve water quality and in exchange receive credits to count towards water quality goals. See more details here!
A 1998 agreement, Phase III Actions for Hypoxia Management, and the 2000 Total Maximum Daily Load (TMDL) plan developed by Connecticut and New York and approved by EPA, called for a 58.5 percent reduction from the baseline level of 59,000 trade equalized pounds per day of nitrogen. This reduction goal had been met in 2016. In 2025, the combined total equalized point source average daily load was 18,909 lbs/day, a rewarding 3,866 lbs/day below the target established in the 2000 TMDL. This represents a 68 percent reduction from the baseline established by the TMDL.
Excess nitrogen loads into the Long Island Sound stimulates excessive growth of phytoplankton and macroalgae leading to eutrophication. When the phytoplankton and macroalgae die, zooplankton or microorganisms (e.g., bacteria) feed on the decay and oxygen is consumed in the bottom waters causing “hypoxic,” with less than 3.0 mg/l of oxygen. These conditions stress or suffocate slow-moving animals that need oxygen to survive and cause other animals to scatter and disappear.
Nitrogen typically comes from point sources, large, fixed sources like wastewater treatment or industrial facilities, and non-point sources, smaller diffuse sources like subpar or failing septic systems, stormwater, residential and agricultural runoff. While the Nutrient Objective now focuses more on nonpoint source controls, it is important to continue to make reductions from point sources to protect and restore water quality in Long Island Sound.
The baseline is the 1990 estimated loading of nitrogen from CT and NY adjusted upward to include the increase of nitrogen from the NYC plants required to end ocean dumping of sewage sludge. The wet slurry of sludge was dewatered and treated at the plant instead of being dumped in the coastal ocean. This increased the amount of nitrogen discharged in the plant effluent. The sewage nitrogen discharge did not increase but was shifted from the ocean discharge of the sludge to the in-plant treatment and subsequent discharge as part of the effluent.
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Trade equalization is a calculation of the effect a pound of nitrogen leaving a point source will eventually have when it reaches Long Island Sound.