Lewisboro pivots to septic district plan for eastern lakes

About 50 people attended a community meeting Tuesday in South Salem on water quality. LOGAN KREISBERG PHOTO

By LOGAN KREISBERG 

Lewisboro officials announced a new strategy Tuesday to combat phosphorus pollution in four town lakes, replacing a years-long effort to build a centralized sewer system with a town-managed septic district using advanced treatment technology. 

The announcement marks a major shift after several years of planning centered on a roughly $40 million sewer project that would serve about 300 homes around lakes Waccabuc, Oscaleta, Rippowam and Truesdale. But as construction estimates continued to rise, officials decided to pursue a more economical approach.

“The decision was made to, rather than chasing an increasing cost to pursue more grants, we decided to consider this pivot to the septic district,” Town Supervisor Tony Gonçalves said during a community meeting.  

Explaining the need for the project, Three Lakes Council President Janet Andersen said all four lakes contain excess phosphorus, a nutrient that triggers aquatic weed growth and algal blooms. She said studies from 2021 pinpointed septic system pollution as a major source of phosphorus entering the lakes. Andersen noted that each pound of phosphorus can produce between 500 and 1,000 pounds of algae or aquatic plants. 

The resulting process, known as eutrophication, lowers water quality and oxygen levels.

Under the previous proposal, wastewater from homes around the lakes would have been piped into a new treatment plant in South Salem. The revised plan would instead leave wastewater treatment at individual homes, replacing conventional septic systems with advanced treatment units maintained through a town-run septic district. 

“The homeowner annual fee is lower with septic than sewer. That’s a major point. It’s less disruptive. We’re not tearing up all the roads. We’re not building a new sewer plant,” said Gonçalves, outlining some of the personal benefits for residents.

This new septic district could include nearly 600 properties, double the amount as the previous plan. Gonçalves said removing about 90% of phosphorus from nearly twice as many homes would roughly double the project’s overall environmental impact.

The plan would provide homes within the district Advanced Septic Treatment Units, or ASTUs, which are designed to remove significantly more phosphorus than conventional systems. 

State and local funding, primarily through New York City Department of Environmental Protection watershed grants, would cover installation costs. Homeowners would pay an estimated $600 annual maintenance fee and about $120 per year in electricity costs. Still the town, specifically a “responsible management entity,” would be responsible for inspections, pumping and maintenance through the septic district. 

Lewisboro must still determine the district’s final boundaries, secure funding and complete the process required under New York town law before the septic district can be established. Once these ducks are in a row, the proposal would then proceed to a public hearing and referendum before the Town Board can formally create the district.

The proposal follows a similar approach already being implemented at Lake Kitchawan, where the town is developing a separate septic district because the lake is too far from the proposed centralized wastewater system. Funding and legal work for the Kitchawan project are expected to wrap up within 90 to 120 days and will guide planning for the eastern lakes district.

More than 50 residents attended the meeting, where questions focused on the technology’s cost, operation and maintenance, along with the scope of construction required on private properties. Several residents questioned whether unspecialized septic systems, and not fertilizer or other sources, are the primary cause of phosphorus pollution in the lakes. 

Others raised concerns about how the proposal would affect their quality of life, including whether each system’s electric blowers would disrupt the natural quietness of the area.

“Two days ago, I was sitting on my deck … a bald eagle came in, missed its catch, and it just made a ripple on the lake,” said Judy Petrow, who has lived on Lake Oscaleta for 40 years. “When you have 100 blowers blowing in your neighborhood, how am I going to hear things like that, which bring joy to my life?”

At the end of the meeting, town officials asked attendees for a show of hands to assess support for the concept of the proposed septic district. Apart from a handful of people who did not raise their hands, nearly everyone indicated they would likely vote on moving the proposal forward despite the concerns previously raised.

“It sounds like they’ve done a lot of good work,” said John Crossman, a Lake Oscaleta resident and member of the lake association. “But it sounds like there’s a lot more work to be done and a lot of questions to be answered.”

Logan Kreisberg, a rising freshman at Northwestern's Medill School of Journalism, is a summer intern at The Recorder.