Water Pollution Control Authority

For the City of Norwalk

About Us:


On March 26, 2002, the Common Council of the City of Norwalk adopted Chapter 113, WATER POLLUTION CONTROL AUTHORITY, of the City Code creating the Water Pollution Control Authority (WPCA) for the City of Norwalk pursuant to Chapter 103, Sections 7-245 through 7-273a, inclusive, of the Connecticut General Statutes.   The WPCA was created to construct, reconstruct, operate and maintain the Sewerage System for the City of Norwalk. The Sewerage System for the City of Norwalk includes three primary components, the collection system, pumping stations, and a wastewater treatment plant located at 60 South Smith Street.


The WPCA Board of Directors consists of nine (9) voting members.   The Chief of Operations and Public Works and the Chief Finance Officer serve as ex officio members without the right to vote.  The WPCA currently employs three full-time staff members.


On September 16, 2019, the WPCA executed a Wastewater Treatment System Operations, Maintenance, and Management Services Agreement (Service Agreement) with SUEZ Water Environmental Services Inc. (SUEZ) for an initial term of 10 years with two additional five-year renewal options.  


In May 2020, the WPCA facilitated a smooth transition of its system operator from OMI, Inc. to SUEZ.  In addition to the SUEZ team’s industry-leading experience operating and maintaining collections systems, the updated Service Agreement between the parties prioritizes asset preservation, enhanced operations, and high quality effluent.  On March 17, 2022, SUEZ merged with Veolia Environment S.A.


On this web site, you will find information about our technology, success over the years, and day-to-day operations. Please contact us if you have any questions or would like additional information. The Norwalk WPCA proudly supports the communities it serves, and offers its facilities to local teachers and classrooms for educational purposes.


System Information 

The WPCA operates and maintains an extensive sanitary sewer collection and treatment system including, 205 miles of sanitary sewer pipeline, 22 pump stations with approximately 6.7 miles of associated force mains an and advanced Wastewater Pollution Control Facility (WPCF) with a design flow of 18 million gallons per day (MGD). There are more than 6,400 sanitary manholes in the system. The WPCF treats wastewater from the City of Norwalk and the Town of Wilton. The WPCA provides sanitary sewer service to approximately 70,000 people. 

Collection System History

The original collection system was installed in the 1880's to convey both sanitary sewage and stormwater during rain events to the Norwalk River and Harbor. In 1931, a Water Pollution Control Facility (WPCF) was constructed on South Smith Street and flows were redirected to the WPCF with the old outfalls acting as high flow overflows during rain events. As the system continued to expand, the sewers were designed to transport only sanitary sewage with a separate system to transport stormwater. Parallel  stormwater systems  were built to separate stormwater flows from the existing combined system. In 1973, approximately  900 acres of heavily developed land were serviced by combined sewers and that was reduced to 525 acres in 1979. Large scale sewer separation project continued through the 1980's  and 1990's separating most of the remaining combined system. Pump stations are used to lift sewage in low laying areas to higher elevations where the gravity portion of the collection system can convey the flow to the WPCF. The WPCA's pump stations are grouped into two categories: wetwell/drywell type stations and submersible stations.  

WPCF History:

 The Norwalk wastewater treatment facility was installed in 1931 and has continued to expand and advance.  In the 1950s, the facility was upgraded with additions and alterations to various equipment and processes.  Primary treatment was added in the 1960s and in the 1970s the plant was upgraded to secondary treatment with activated biological treatment. In the 1970s, additional wet weather treatment and pumping systems were added. In the 1990s, additional treatment technologies were added for biological nutrient removal (BNR) as part of the Long Island Sound Conservation and Management Plan. In 2012 the CSO/Wet Weather Preliminary Treatment building went online and can handle wet weather flows up to a peak of 95 MGD.  Wet weather flows up to 30 MGD receive full treatment and flow above 30 mgd receives wet weather treatment before being discharged into the Norwalk River. In 2020 improved chlorination and dechlorination was added to wet weather treatment.

Billing/Fee Information:



Sewer Use Charges:






  • Single Family
  • Two Family
  • Three Family
  • Four Family
  • Apartment/Condominium Unit
  • In-Law Unit/Accessory Apartment









Commercial and Mixed Use Properties (up to 110,000 gallons)



Commercial and Mixed Use Properties (over 110,000 gallons)


$546.00 plus $9.87 per 1,000 gallons over 110,000 gallons

Temporary Discharge


$9.87 per 1,000 gallons

Late Payment Interest


Returned Check Fee


1.5% per month or fraction thereof, 18% per annum



Use classification is based on the Tax Assessor’s Land Use Codes (LUCs) as follows(1):

  • §  Residential:  100, 101, 101V, 102, 103, 104, 105, 105V, 106, 107, 108, 109, 113V, 152, 172, 911, 957, 962, 963, 965, 976N, 979, 979N
  • Commercial and Mixed-Use:     1, 108C, 182, 200V, 201V, 203V, 205V, 206V, 211V, 300, 301, 305, 400, 401, 410, 718, 720, 900, 902, 904, 909, 916, 917, 918, 920V, 921V, 922V, 923V, 924, 925, 926, 927, 928, 931, 933V, 934V, 935V, 938, 946, 946N, 947, 948, 950, 951V, 952, 955, 961V, 964, 967, 969, 970, 975, 977, 980, 981V, 936

(1) Parcels that have both residential and commercial LUCs are classified as “Commercial and Mixed-Use” for billing




Industrial Pre-treatment Program (IPP) Fees:


Industrial Pretreatment Program (IPP) Registration

(includes industrial dischargers and food preparation establishments)


Fee is Waived


Industrial Pretreatment Program (IPP) Fees

Administration Fee:


High Strength Surcharge Fee (sample results exceeding 250 mg/l for BOD and/or TSS, or 100 mg/l for O&G):


Noncompliance Fee:


IPP Fee (Total):


IPP Fee ($) = Administrative Fee ($) + High Strength Surcharge Fee ($) (if applicable) + noncompliance fee ($) (if applicable)










Connection Fee Calculation:


Water Meter Size

Sewer Connection Fee

5/8 inch


3/4 inch


1 inch


1-1/2 inch


2 inch


3 inch


4 inch


6 inch


8 inch


10 inch


12 inch


Fats, Oils & Grease (FOG) Program


What is FOG?


FOG is fats, oils, and grease can build-up in private and City sanitary sewer pipes. When FOG is washed down the sink or toilet it coats and sticks to the inside of sewer pipes.


What are the most common sources of FOG?


FOG comes from meat fats (bacon, sausage) lard, cooking oil, butter or margarine, food scraps, baking products, milk, ice cream, yogurt, sour cream, cream based sauces, salad dressings, cheeses and mayonnaise.


Why is FOG a Problem?


Sewer pipes can become clogged by FOG and cause backups into basements, roadways, and water bodies. Sewer backups create health hazards, can result in expensive property damage, and threaten the environment. FOG Large amounts of FOG in the wastewater cause trouble in the collection system pipes. It decreases pipe capacity and, therefore, requires that piping systems to be cleaned more often and/or some piping to be replaced sooner than otherwise expected. FOG also hamper effective treatment at the wastewater treatment plant.

Private lateral and City sewer pipe with FOG:


Sewage overflow due to FOG blockage:

What Can I Do?



Resources for Business:


  • Installing a pretreatment system, in the form of a grease recovery unit to assist  with removing FOG from related sinks & drains
  • Remove, scrape and wipe contents from plates and pans into garbage containers prior to washing
  • Provide screens in sinks and drains to collect missed scraps
  • Maintain grease recovery units in accordance with manufacturing and local authority requirements
  • Educate and communicate: review daily fog prevention practices with new and current staff
  • Record keeping: keep a grease recovery unit maintenance log current


Commercial Property FOG Resources

  • Grease Trap (GRU) Sizing Calculations
  • FOG General Permit
  • Maintenance Log
  • AGRU Sample Port and Shutoff Valve Detail
  • FOG Program Packet (5-11-16)


Resources for Residents:


  •  Never pour oil and grease down the sink, toilet or any drains.

         2.  Put used oil and grease in covered containers and cans for proper disposal.

         3.  Wipe down greasy pots and pans with a dry paper towel and dispose in the trash.

         4.  Scrape food scraps and discards into the trash. Avoid using the garbage disposal.

         5.   Do not rely on a garbage disposal to get rid of grease it grinds it into smaller pieces but it does not keep grease from going down the                   drain.

          6. Do not run hot water over greasy pans or use hot water to wash grease down the drain. The grease will eventually cool and congeal in                your pipe.