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Community Water System · PWS NY5903442

New Castle/Stanwood W.D.

Chappaqua, New York 10514 - drinking water served from surface water sources to 17,116 people, tracked in EPA SDWIS and UCMR5.

17,116
People served
105
EPA violations
4
Health-based
No PFAS
UCMR5 result

The verdict

EPA records 105 drinking-water violations at New Castle/Stanwood W.D., 4% of them health-based - above the New York per-system average.

105
Total EPA violations on record
4%
Health-based (MCL / treatment failure)
17,116
People served by this system
0
PFAS compounds detected (UCMR5)

Water Quality Snapshot: New Castle/Stanwood W.D.

New Castle/Stanwood W.D. is a local-owned community water system that delivers drinking water to 17,116 residents in Chappaqua, New York (Westchester County) through 5,183 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 105 total violations for this system , of which 4 (4%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 95 monitoring and reporting violations are on file. The most recent violation on record dates to 2018.

The most frequently cited contaminant at this system is TTHM, recorded in 8 violations (MR). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.

Across New York, EPA tracks 8,098 public water systems serving 19,294,951 people, with 552,003 cumulative violations and 26,817 health-based violations on record. About 94% of systems in the state carry at least one violation, and state-wide the average per system is 68.2 violations. Statewide, 129 of 332 UCMR5-tested systems have reported PFAS detections (38.9%).

New Castle/Stanwood W.D.'s 105 violations sit above the New York average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.

Population Served
17,116
Total Violations
105
Health-Based Violations
4
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
5,183
County
Westchester
School/Daycare
No
MCL Violations
4
Monitoring Violations
95
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
TTHM MR 8 2018
Total Haloacetic Acids (HAA5) MR 8 2018
Beryllium, Total MR 5 2002
Selenium MR 5 2002
Thallium, Total MR 5 2002
Cadmium MR 5 2002
Nitrate-Nitrite MR 5 2002
Barium MR 5 2002
Chromium MR 5 2002
Fluoride MR 5 2002
Nickel MR 5 2002
Nitrite MR 5 2002
Mercury MR 5 2002
CYANIDE MR 5 2002
Antimony, Total MR 5 2002
Nitrate MR 5 2002
Arsenic MR 5 2002
Coliform (TCR) MR 4 2007
Coliform (TCR) MCL 4 2009

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 116 samples detected PFAS.

Contaminant Date Result MRL Status
9Cl-PF3ONS 9/12/2023 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFBS 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFUnA 9/12/2023 <2.00 ppt 2.00 ppt Not Detected
PFNA 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
PFOS 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
PFOA 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
PFDA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFDoA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxS 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFBA 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFHpS 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeS 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
NFDHA 9/12/2023 <20.00 ppt 20.00 ppt Not Detected
PFEESA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFMBA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
HFPO-DA 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFMPA 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
ADONA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
4:2 FTS 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
6:2 FTS 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFTA 9/12/2023 <8.00 ppt 8.00 ppt Not Detected
PFTrDA 9/12/2023 <7.00 ppt 7.00 ppt Not Detected
NEtFOSAA 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 9/12/2023 <6.00 ppt 6.00 ppt Not Detected
PFPeA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFBA 6/20/2023 <5.00 ppt 5.00 ppt Not Detected
HFPO-DA 6/20/2023 <5.00 ppt 5.00 ppt Not Detected
ADONA 6/20/2023 <3.00 ppt 3.00 ppt Not Detected
9Cl-PF3ONS 6/20/2023 <2.00 ppt 2.00 ppt Not Detected
PFUnA 6/20/2023 <2.00 ppt 2.00 ppt Not Detected
6:2 FTS 6/20/2023 <5.00 ppt 5.00 ppt Not Detected
PFPeS 6/20/2023 <4.00 ppt 4.00 ppt Not Detected
PFDA 6/20/2023 <3.00 ppt 3.00 ppt Not Detected
4:2 FTS 6/20/2023 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 6/20/2023 <5.00 ppt 5.00 ppt Not Detected
PFMPA 6/20/2023 <4.00 ppt 4.00 ppt Not Detected
PFPeA 6/20/2023 <3.00 ppt 3.00 ppt Not Detected
PFMBA 6/20/2023 <3.00 ppt 3.00 ppt Not Detected
NFDHA 6/20/2023 <20.00 ppt 20.00 ppt Not Detected
PFHxA 6/20/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpS 6/20/2023 <3.00 ppt 3.00 ppt Not Detected
PFOA 6/20/2023 <4.00 ppt 4.00 ppt Not Detected
PFEESA 6/20/2023 <3.00 ppt 3.00 ppt Not Detected
PFTrDA 6/20/2023 <7.00 ppt 7.00 ppt Not Detected
11Cl-PF3OUdS 6/20/2023 <5.00 ppt 5.00 ppt Not Detected
PFOS 6/20/2023 <4.00 ppt 4.00 ppt Not Detected

Verify This Water System

The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for New Castle/Stanwood W.D..

Federal Source of Truth

EPA SDWIS, Federal Reports

EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:

View PWS ID NY5903442 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

New York Drinking Water Authority

New York State Department of Health, Public Water Systems is the primacy agency that licenses and inspects New Castle/Stanwood W.D. under EPA-delegated authority.

Open NY regulator portal

Source: New York State Department of Health, Public Water Systems

Violation Timeline

Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.

Year (latest) Contaminant Category Count EPA Record
2018 TTHM MR 8 SDWIS / NY5903442 / 2950
2018 Total Haloacetic Acids (HAA5) MR 8 SDWIS / NY5903442 / 2456
2009 Coliform (TCR) MCL 4 SDWIS / NY5903442 / 3100
2007 Coliform (TCR) MR 4 SDWIS / NY5903442 / 3100
2002 Beryllium, Total MR 5 SDWIS / NY5903442 / 1075
2002 Selenium MR 5 SDWIS / NY5903442 / 1045
2002 Thallium, Total MR 5 SDWIS / NY5903442 / 1085
2002 Cadmium MR 5 SDWIS / NY5903442 / 1015
2002 Nitrate-Nitrite MR 5 SDWIS / NY5903442 / 1038
2002 Barium MR 5 SDWIS / NY5903442 / 1010
2002 Chromium MR 5 SDWIS / NY5903442 / 1020
2002 Fluoride MR 5 SDWIS / NY5903442 / 1025
2002 Nickel MR 5 SDWIS / NY5903442 / 1036
2002 Nitrite MR 5 SDWIS / NY5903442 / 1041
2002 Mercury MR 5 SDWIS / NY5903442 / 1035

How New Castle/Stanwood W.D. Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric New Castle/Stanwood W.D. New York avg Federal benchmark
Total violations 105 68.2 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 4 3.3 Indicates a contaminant exceeded a federal MCL
PFAS detection None 38.9% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 17,116 2,383 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 8,098 regulated public water systems in New York.

Federal MCL reference, Safe Drinking Water Act thresholds ▼
Contaminant Federal MCL / Action Level Note
Lead 0 mg/L (Action Level: 0.015 mg/L) Lead and Copper Rule treatment technique
Arsenic 0.010 mg/L (10 ppb) Health-based MCL since 2006
Total Coliform Treatment technique (RTCR) Indicator organism, monitoring trigger
PFOA / PFOS (PFAS) 4.0 ppt each (final 2024 rule) Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026)
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is New Castle/Stanwood W.D. water safe to drink? ▼
New Castle/Stanwood W.D. (PWS ID: NY5903442) has 105 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 17,116 people using Surface Water sources.
How many people does New Castle/Stanwood W.D. serve? ▼
New Castle/Stanwood W.D. serves 17,116 people in Chappaqua, New York. It is a Local-owned system using Surface Water water sources with 5,183 service connections.
What type of violations does New Castle/Stanwood W.D. have? ▼
New Castle/Stanwood W.D. has 105 total violations: 4 health-based violations (MCL exceedances or treatment failures), 95 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in New Castle/Stanwood W.D. water? ▼
No. New Castle/Stanwood W.D. was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does New Castle/Stanwood W.D. use? ▼
New Castle/Stanwood W.D. uses Surface Water as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
Where does this data come from? ▼
All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. PFAS data from EPA UCMR5 monitoring program (2023-2025). This data is provided for informational purposes only.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.