Short answer: Check your mail first: since January 1, 2026, every property connected to a Suffolk County sewer gets its own quarterly bill from the Suffolk County Wastewater Management District, and sewer charges no longer appear on the property tax bill. If you don't get that bill, your house is very likely on a cesspool or septic system, which is true for most homes in Suffolk County.
Why it matters
When every drain backs up, the fix depends on where your wastewater goes. On a sewer, the problem is usually in your house line or lateral, and a plumber clears it. On a cesspool or septic system, a full or failing system needs a licensed liquid-waste contractor to pump or replace it. Knowing which one you have before you call saves a wasted visit.
Most of Suffolk County isn't sewered. The County says nearly 70% of Suffolk homes use cesspools and septic systems.
Four ways to check
- Look for a County sewer bill. Effective January 1, 2026, all Suffolk County sewer districts were consolidated into the Suffolk County Wastewater Management District. Connected properties get a separate bill (quarterly for homes), and sewer charges no longer appear on your property tax bill. A single-family home is billed as 1 "SFE" (single family equivalent, which the County estimates at 225 gallons a day).
- Ask the County. Suffolk County Public Works says that if you're unsure of your connection status, email sewerconnectionstatus@suffolkcountyny.gov and a representative will contact you. Sewer billing questions go to (631) 852-4060, weekdays 8 AM to 4 PM.
- Check the County sewered-areas map. Suffolk County Planning publishes large PDF maps of sewered areas by town. For this area, open "Brookhaven North." It shows Suffolk County Sewer District 11 (Selden) as the main district in this part of town, plus smaller ones nearby such as Port Jefferson (CSD-01), Stony Brook (CSD-10), SUNY at Stony Brook (CSD-21) and Holbrook-Birchwood (CSD-12). The maps are dated September 2012, so treat them as a starting point, not proof for a single house.
- Look in the yard and basement. Many cesspool and septic systems have a round concrete cover or a buried lid in the yard, often within a few feet of where the main drain pipe leaves the house. Old inspection reports, a home-sale survey, or pumping receipts from a past owner are also good clues. If you can't find anything, a liquid-waste contractor or a plumber with a camera can trace where the line goes.
About Sewer District 11 (Selden)
- Created by the Suffolk County Legislature with State Comptroller approval in 1977 and extended in 1983.
- Serves about 10,500 single family equivalents, including properties connected through agreements (County Legislature resolution, June 2025).
- Its treatment plant (tertiary treatment, groundwater discharge) has a permitted flow of 2.36 million gallons a day, per the County's sewage treatment plant table.
- Being near the district, or on a street with a sewer line, doesn't mean your house is connected. Only the County can confirm connection status.
If you are on a sewer
- For a problem with your sewer connection in any area other than the Southwest Sewer Area, the County's line is (631) 852-4109. A backup inside your own house line is usually a plumber's job; the County handles the public system.
- You can't stop the sewer bill by turning off the water. The County says every property with a viable connection is billed, and disconnecting is only allowed when the building is being demolished.
- Unpaid sewer charges become a lien on the property and can show up on the Town tax bill as arrears.
If you're on a cesspool or septic system
- A failed cesspool can't be replaced with another cesspool in Suffolk; the minimum is a septic tank plus a leaching structure. See replacing a failed cesspool in Suffolk County.
- Suffolk's Septic Improvement Program grants are for homes that are not connected to sewers and not in a proposed sewer area, so knowing your status matters before you apply.
- Pumping schedule: see how often a cesspool should be pumped on Long Island.
Sources
- Suffolk County Department of Public Works, Sewer Billing Services FAQ (2026 consolidation into the Wastewater Management District, separate bills, connection-status email, SFE = 225 gpd, service problem lines, liens, no disconnection except demolition)
- Suffolk County Planning, Sewered Areas and Sewage Treatment Plants Maps (Brookhaven North map, Sept. 27, 2012) and district and plant tables (CSD-11 Selden plant permitted flow 2.36 mgd, tertiary, groundwater outfall)
- Suffolk County Legislature, Resolution No. 658-2025 (Sewer District No. 11 Selden created 1977, extended 1983, about 10,500 single family equivalents)
- Suffolk County Septic Improvement Program (share of homes on cesspools and septic; grant eligibility)
General information, checked against Suffolk County pages on Oct 26, 2026. Only the County can confirm whether a specific property is connected.
Common questions
How do I know if my house is connected to the sewer in Suffolk County?
Since January 1, 2026, connected properties get a separate quarterly sewer bill from the Suffolk County Wastewater Management District. If you're unsure, Suffolk County Public Works says to email sewerconnectionstatus@suffolkcountyny.gov and a representative will contact you.
Is Centereach on public sewers?
Most Suffolk County homes use cesspools or septic systems rather than sewers. The main County sewer district in this part of Brookhaven is Sewer District 11 (Selden), but being nearby doesn't mean a particular house is connected. Check for a County sewer bill or ask the County.
Why don't I see sewer charges on my tax bill anymore?
Suffolk consolidated its sewer districts on January 1, 2026. Sewer charges moved off the property tax bill and onto a separate County sewer bill.
Can I disconnect from the sewer to stop the bill?
No. The County says every property with a viable connection is billed, and disconnecting is only allowed when the building is being demolished.
Who do I call for a sewer backup in Selden?
If the backup is inside your house line, a plumber. For a problem with the public sewer connection outside the Southwest Sewer Area, Suffolk County lists (631) 852-4109.
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Related services
We're a referral service, not a plumber. Centereach Plumber Connect doesn't do plumbing work or hold plumbing licenses. When you send a request, we try to match you with one independent local plumber. You decide whether to hire them, with no obligation. We may be paid by the plumbers we refer. Always confirm the plumber's Suffolk County license, insurance and a written price before work starts. Look up a Suffolk County license.