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GREGORY

PWS ID: SD4600145 · GREGORY, South Dakota 57533

GREGORY serves 1,221 people in GREGORY, South Dakota using Groundwater water sources. It has 84 recorded EPA violations, including 4 health-based violations. No PFAS contamination was detected in UCMR5 testing.

Water Quality Snapshot: GREGORY

GREGORY is a local-owned community water system that delivers drinking water to 1,221 residents in GREGORY, South Dakota (Gregory County) through 741 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 84 total violations for this system , of which 4 (5%) are health-based — meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 64 monitoring and reporting violations are on file. The most recent violation on record dates to 2019.

The most frequently cited contaminant at this system is Lead and Copper Rule, recorded in 7 violations (MR). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

Across South Dakota, EPA tracks 654 public water systems serving 915,901 people, with 56,254 cumulative violations and 8,399 health-based violations on record. About 92% of systems in the state carry at least one violation, and state-wide the average per system is 86 violations. GREGORY's 84 violations sit below the South Dakota average. Statewide, 42 of 49 UCMR5-tested systems have reported PFAS detections (85.7%). 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
1,221
Total Violations
84
Health-Based Violations
4
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Local
Connections
741
County
Gregory
School/Daycare
No
MCL Violations
0
Monitoring Violations
64
Treatment Tech Violations
4

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Lead and Copper Rule MR 7 2005
Gross Alpha, Excl. Radon and U MR 3 1988
Combined Radium (-226 and -228) MR 3 1988
Nitrate MR 3 1995
Cadmium MR 2 1989
Chromium MR 2 1989
Mercury MR 2 1989
Selenium MR 2 1989
LASSO MR 2 1999
Heptachlor MR 2 1999
Heptachlor epoxide MR 2 1999
Atrazine MR 2 1999
Benzo(a)pyrene MR 2 1999
Hexachlorocyclopentadiene MR 2 1999
Endrin MR 2 1999
Barium MR 2 1989
Methoxychlor MR 2 1999
Di(2-ethylhexyl) adipate MR 2 1999
Total Polychlorinated Biphenyls (PCB) MR 2 1999
Coliform (TCR) MR 2 1991
Fluoride MR 2 1989
HEXACHLOROBENZENE MR 2 1999
BHC-GAMMA MR 2 1999
Simazine MR 2 1999
Chlordane MR 2 1999
Di(2-ethylhexyl) phthalate MR 2 1999
Arsenic MR 2 1989
Toxaphene MR 2 1999
Stage 1 Disinfectants and Disinfection Byproducts Rule TT 2 2004
Groundwater Rule TT 2 2019

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 GREGORY.

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 SD4600145 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

South Dakota Drinking Water Authority

South Dakota'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 SD 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
2019 Groundwater Rule TT 2 SDWIS / SD4600145 / 0700
2005 Lead and Copper Rule MR 7 SDWIS / SD4600145 / 5000
2004 Stage 1 Disinfectants and Disinfection Byproducts Rule TT 2 SDWIS / SD4600145 / 0400
2000 Lead and Copper Rule Other 1 SDWIS / SD4600145 / 5000
1999 LASSO MR 2 SDWIS / SD4600145 / 2051
1999 Heptachlor MR 2 SDWIS / SD4600145 / 2065
1999 Heptachlor epoxide MR 2 SDWIS / SD4600145 / 2067
1999 Atrazine MR 2 SDWIS / SD4600145 / 2050
1999 Benzo(a)pyrene MR 2 SDWIS / SD4600145 / 2306
1999 Hexachlorocyclopentadiene MR 2 SDWIS / SD4600145 / 2042
1999 Endrin MR 2 SDWIS / SD4600145 / 2005
1999 Methoxychlor MR 2 SDWIS / SD4600145 / 2015
1999 Di(2-ethylhexyl) adipate MR 2 SDWIS / SD4600145 / 2035
1999 Total Polychlorinated Biphenyls (PCB) MR 2 SDWIS / SD4600145 / 2383
1999 HEXACHLOROBENZENE MR 2 SDWIS / SD4600145 / 2274

How GREGORY Compares

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

Metric GREGORY South Dakota avg Federal benchmark
Total violations 84 86 SDWA compliance — any non-zero count is a recorded breach
Health-based violations 4 12.8 Indicates a contaminant exceeded a federal MCL
PFAS detection None 85.7% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 1,221 1,400 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 654 regulated public water systems in South Dakota.

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
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is GREGORY water safe to drink? ▼
GREGORY (PWS ID: SD4600145) has 84 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 1,221 people using Groundwater sources.
How many people does GREGORY serve? ▼
GREGORY serves 1,221 people in GREGORY, South Dakota. It is a Local-owned system using Groundwater water sources with 741 service connections.
What type of violations does GREGORY have? ▼
GREGORY has 84 total violations: 4 health-based violations (MCL exceedances or treatment failures), 64 monitoring/reporting violations, and 4 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in GREGORY water? ▼
No PFAS testing data is available for GREGORY under the EPA's UCMR5 monitoring program.
What water source does GREGORY use? ▼
GREGORY 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.

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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.

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