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Community Water System · PWS 010307001

Aquinnah Wampanoag

Chilmark, EPA Region 1 — Tribal Water Systems 02535 - drinking water served from groundwater sources to 89 people, tracked in EPA SDWIS and UCMR5.

89
People served
240
EPA violations
20
Health-based
Untested
UCMR5 result

The verdict

EPA records 240 drinking-water violations at Aquinnah Wampanoag, 8% of them health-based.

240
Total EPA violations on record
8%
Health-based (MCL / treatment failure)
89
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Aquinnah Wampanoag

Aquinnah Wampanoag is a native american-owned community water system that delivers drinking water to 89 residents in Chilmark, EPA Region 1 — Tribal Water Systems through 32 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 240 total violations for this system , of which 20 (8%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 210 monitoring and reporting violations are on file. The most recent violation on record dates to 2025.

The most frequently cited contaminant at this system is Nitrate, recorded in 24 violations (MR). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

EPA Region 1 — Tribal Water Systems has thousands of regulated public water systems tracked by EPA under the Safe Drinking Water Act.

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
89
Total Violations
240
Health-Based Violations
20
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Native American
Connections
32
School/Daycare
No
MCL Violations
14
Monitoring Violations
210
Treatment Tech Violations
6

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Nitrate MR 24 2025
Coliform (TCR) MR 20 2014
Lead and Copper Rule MR 15 2024
Coliform (TCR) MCL 14 2011
Arsenic MR 6 2023
Cadmium MR 6 2023
Chromium MR 6 2023
CYANIDE MR 6 2023
Fluoride MR 6 2023
Mercury MR 6 2023
Antimony, Total MR 6 2023
Thallium, Total MR 6 2023
E. COLI MR 6 2016
Revised Total Coliform Rule RPT 6 2025
Selenium MR 6 2023
Beryllium, Total MR 6 2023
Lead and Copper Rule TT 6 2009
Barium MR 6 2023
Endrin MR 3 2017
Toxaphene MR 3 2017
Di(2-ethylhexyl) adipate MR 3 2017
Di(2-ethylhexyl) phthalate MR 3 2017
Hexachlorocyclopentadiene MR 3 2017
Atrazine MR 3 2017
Heptachlor MR 3 2017
2,4-D MR 3 2017
HEXACHLOROBENZENE MR 3 2017
Benzo(a)pyrene MR 3 2017
Total Polychlorinated Biphenyls (PCB) MR 3 2017
1,2-DIBROMO-3-CHLOROPROPANE MR 3 2017

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 Aquinnah Wampanoag.

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 010307001 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

EPA Region 1 — Tribal Water Systems Drinking Water Authority

EPA Region 1 — Tribal Water Systems's primacy agency administers the Safe Drinking Water Act locally. Search EPA SDWIS for the current state contact, or use the state's public health or environment department portal.

Find 01 regulator via EPA SDWIS

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
2025 Nitrate MR 24 SDWIS / 010307001 / 1040
2025 Revised Total Coliform Rule RPT 6 SDWIS / 010307001 / 8000
2024 Lead and Copper Rule MR 15 SDWIS / 010307001 / 5000
2023 Arsenic MR 6 SDWIS / 010307001 / 1005
2023 Cadmium MR 6 SDWIS / 010307001 / 1015
2023 Chromium MR 6 SDWIS / 010307001 / 1020
2023 CYANIDE MR 6 SDWIS / 010307001 / 1024
2023 Fluoride MR 6 SDWIS / 010307001 / 1025
2023 Mercury MR 6 SDWIS / 010307001 / 1035
2023 Antimony, Total MR 6 SDWIS / 010307001 / 1074
2023 Thallium, Total MR 6 SDWIS / 010307001 / 1085
2023 Selenium MR 6 SDWIS / 010307001 / 1045
2023 Beryllium, Total MR 6 SDWIS / 010307001 / 1075
2023 Barium MR 6 SDWIS / 010307001 / 1010
2020 Revised Total Coliform Rule MON 1 SDWIS / 010307001 / 8000

How Aquinnah Wampanoag Compares

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

Metric Aquinnah Wampanoag EPA Region 1 — Tribal Water Systems avg Federal benchmark
Total violations 240 - SDWA compliance, any non-zero count is a recorded breach
Health-based violations 20 - Indicates a contaminant exceeded a federal MCL
PFAS detection None - EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 89 - Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across all regulated public water systems in EPA Region 1 — Tribal Water Systems.

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 Aquinnah Wampanoag water safe to drink? ▼
Aquinnah Wampanoag (PWS ID: 010307001) has 240 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 89 people using Groundwater sources.
How many people does Aquinnah Wampanoag serve? ▼
Aquinnah Wampanoag serves 89 people in Chilmark, EPA Region 1 — Tribal Water Systems. It is a Native American-owned system using Groundwater water sources with 32 service connections.
What type of violations does Aquinnah Wampanoag have? ▼
Aquinnah Wampanoag has 240 total violations: 20 health-based violations (MCL exceedances or treatment failures), 210 monitoring/reporting violations, and 6 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Aquinnah Wampanoag water? ▼
No PFAS testing data is available for Aquinnah Wampanoag under the EPA's UCMR5 monitoring program.
What water source does Aquinnah Wampanoag use? ▼
Aquinnah Wampanoag uses Groundwater 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. 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.