Norwalk Sewage Overflows

Norwalk’s Inner Harbor scored significantly worse than the Middle or Outer portions did in the 2019 Unified Water Study.

Location: Norwalk, CT | Status: Active

Summary: Poorly maintained sewage collection systems can fall into a state of disrepair that can result in chronic sewage spills, impacting the health of Connecticut residents and our shared environment. A review of Connecticut’s Sewage Right to Know database showed that the City of Norwalk has chronic bypasses from its collection system, despite two recent administrative orders issued by the EPA in 2010 and 2017. These sewage bypasses result in the discharge of raw sewage into the Norwalk River, Five Mile River, and Long Island Sound. In 2020, Norwalk reported two illegal bypasses reported; in 2021, Norwalk reported eight illegal bypasses; and in 2022, to date, Norwalk reported 4 illegal bypasses. While some progress is being made in eliminating these bypasses, there are still unresolved issues of excess flow resulting in bypasses during storm events and failing sewer pipes that require urgent rehabilitation.

Norwalk also relies on the use of a CSO outfall at its treatment plant when flows exceed plant capacity, which discharges partially treated sewage into Norwalk Harbor. Norwalk also operates an emergency outfall, again to accommodate excess flow, that discharges raw sewage into the Harbor. There needs to be a plan to address this excess flow and eliminate the use of these outfalls.

Save the Sound is tracking compliance with the EPA consent orders, through discussions with Norwalk staff, EPA, and DEEP, and review of compliance deliverables. Save the Sound submitted comments on the renewal of Norwalk’s wastewater treatment plant NPDES permit and participated in a public informational hearing that we requested. As a result of our advocacy during the permit renewal proceedings, CT Department of Energy and Environmental Protection issued a consent order in May 2022. DEEP’s consent order requires the city to develop and implement plans to study and remove excess flow from the collection system within 5 years; eliminate an unpermitted emergency overflow outfall within 5 years; and either provide primary treatment to a permitted sewage overflow outfall or eliminate use of that outfall within 10 years. These efforts will reduce the discharge of raw sewage into Norwalk’s waterways and should improve water quality in Norwalk Harbor. DEEP will also soon establish a Total Maximum Daily Load (TMDL), an enforceable plan to address water quality problems, for Norwalk’s polluted inner harbor. We successfully advocated for a requirement that Norwalk monitor the harbor to provide information for the upcoming TMDL. We’ll continue to push DEEP to move forward with the process and finally bring the inner Norwalk Harbor up to Clean Water Act standards.

Latest Step: DEEP issued a consent order addressing Norwalk’s sewage collection system and excess sewage flows. Pursuant to this consent order, Norwalk submitted a Sanitary Sewer Collection System Master Plan for DEEP review and approval.

Next Step: Norwalk must promptly implement the approved Sanitary Sewer Collection System Master Plan. Norwalk must also submit a Wastewater Treatment Facilities Plan to DEEP by the end of June 2023. Save the Sound will continue to review Norwalk’s compliance with the Clean Water Act and the DEEP consent order, including any deliverables. Save the Sound will also ensure that the public is informed about these ongoing efforts by Norwalk.

Further Reading:

Action Opportunities:

Last Updated: November 1, 2022


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