Public water system · NY5103271
ActiveGreenlawn Water District
At a glance
Greenlawn Water District (PWSID NY5103271) is an active community water system in Suffolk County, New York. It reports serving 42,000 people through 11,500 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
42,000
Service connections
11,500
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Greenlawn Water District compare with other water systems in Suffolk County?
By EPA's size categories, Greenlawn Water District is a large system (10,001 to 100,000 people). Suffolk County has 151 active public water systems, and Greenlawn Water District is the 3rd-largest of them by population served. Its population served is about 4.6 times the county average of 9,192 people per system, and accounts for 3% of the 1,387,972 people reported by systems filed under the county. Across New York, the 8,167 active systems average 2,374 people each. Nationally, the average active community water system reports serving 6,703 people, so Greenlawn Water District is about 6.3 times that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. New York has 2,281 active community water systems, 28% of the state's 8,167 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 7,096 New York systems (87%) list groundwater as their primary source.
Who owns and regulates Greenlawn Water District?
EPA lists Greenlawn Water District as owned by a local government. The NY state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 38 of the 151 active systems in Suffolk County (25%) are also owned by a local government.
Does Greenlawn Water District have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2026. The violations listed here began between January 2024 and January 2026. By type: 12 monitoring and reporting. The contaminant or rule involved most often is Nitrate-Nitrite (2 of them). EPA lists 12 as archived. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | No | Archived |
| 2025-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | No | Archived |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Thalliumcode 1085 | No | Archived |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Antimonycode 1074 | No | Archived |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Berylliumcode 1075 | No | Archived |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nickelcode 1036 | No | Archived |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | No | Archived |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Bariumcode 1010 | No | Archived |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chromiumcode 1020 | No | Archived |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Archived |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Mercurycode 1035 | No | Archived |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Seleniumcode 1045 | No | Archived |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Greenlawn Water District: frequently asked questions
Who runs Greenlawn Water District?
Greenlawn Water District (PWSID NY5103271) is a community water system owned by a local government. It is regulated by the NY state drinking water program.
How many people does Greenlawn Water District serve?
Greenlawn Water District reports serving 42,000 people through 11,500 service connections in Suffolk County, New York.
Where does Greenlawn Water District get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Greenlawn Water District have any drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2026. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Greenlawn Water District's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2026. For current results, consult the system's annual water quality report, EPA ECHO, or the NY state drinking water program.
Where can I find Greenlawn Water District's water quality report?
As a community water system, Greenlawn Water District must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Suffolk County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Suffolk County Water Authority | Suffolk | 1,100,000 | Community | Groundwater |
| South Huntington Water District | Suffolk | 81,760 | Community | Groundwater |
| Riverhead Water District | Suffolk | 35,000 | Community | Groundwater |
| Dix Hills Water District | Suffolk | 34,522 | Community | Groundwater |
| Smithtown Water District | Suffolk | 19,635 | Community | Purchased groundwater |
| Hampton Bays Water District | Suffolk | 12,500 | Community | Groundwater |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Greenlawn Water District, PWSID NY5103271, New York”, https://aquacensus.com/water-systems/new-york/greenlawn-water-district-ny5103271 (data as of October 1, 2026).