In an updated disclosure Saturday afternoon, the Mamaroneck Sanitary Sewer District Wastewater Treatment Plant (MMWWTP) by Harbor Island Park on the Boston Post Road in Mamaroneck revised its release figures of partially treated wastewater into the Long Island Sound downward to 348,070 gallons. The original estimate given in the disclosure on Friday was 5,000,000 gallons. No other context was given regarding the revision. The release of wastewater was made on Friday, December 19, 2025 at 11:00am.
The reason given for the discharge was “weather conditions – short term partial blend wet weather event” and the discharge was partially treated with disinfection. The Mamaroneck plant is operated by Westchester County and typically discharges treated effluent through a 60-inch outfall pipe extending approximately half a mile into the Long Island Sound.
It is not unusual for rainstorms to overwhelm wastewater infrastructure, causing the release of waste that has not been fully treated.
The Friday and Saturday disclosures were made under the 2013 Sewage Pollution Right to Know (SPRTK) rules administered by the New York State department of Environmental Conservation (NYDEC). Notifications of sewage discharges help the public avoid boating, fishing or swimming in waterbodies that may contain illness causing bacteria. Especially in the summertime, high bacteria counts will lead to beach closures for both public and private beaches in Rye and along the sound shore.
It’s troubling that any discharge of treated or untreated sewage is occurring in our area. That it is going into L.I. Sound is dangerous and should be stopped and replaced by a smarter treatment system.
Ecologically unsound methods of waste treatment combined with larger global change heating up the oceans and air is a fast tobogan ride into a brick wall for our future.
See this as the small matter it is and multiply it in many other towns up the east coast alone, and we have really hard problems to solve. We read that much of the world has no sewage controls.
The solution to sewage discharges begins here in our back yard. Let’s start thinking and stop delaying.