ONIDA
PWS ID: SD4600233 · ONIDA, South Dakota 57564
ONIDA serves 658 people in ONIDA, South Dakota using Surface Water water sources. It has 139 recorded EPA violations, including 42 health-based violations. No PFAS contamination was detected in UCMR5 testing.
Water Quality Snapshot: ONIDA
ONIDA is a local-owned community water system that delivers drinking water to 658 residents in ONIDA, South Dakota (Sully County) through 410 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 139 total violations for this system , of which 42 (30%) are health-based — meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 66 monitoring and reporting violations are on file. The most recent violation on record dates to 2004.
The most frequently cited contaminant at this system is Coliform (TCR), recorded in 45 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. ONIDA's 139 violations sit above 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.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 410
- County
- Sully
- School/Daycare
- No
- MCL Violations
- 42
- Monitoring Violations
- 66
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 45 | 2003 |
| Coliform (TCR) | MCL | 33 | 1997 |
| Coliform (TCR) | Other | 13 | 1998 |
| Lead and Copper Rule | MR | 9 | 2000 |
| Combined Radium (-226 and -228) | MCL | 8 | 1997 |
| Combined Radium (-226 and -228) | MR | 5 | 1996 |
| Gross Alpha, Excl. Radon and U | MR | 5 | 1996 |
| Consumer Confidence Rule | Other | 4 | 2002 |
| Lead and Copper Rule | Other | 2 | 2001 |
| Asbestos | MR | 2 | 1993 |
| Public Notice | Other | 1 | 2004 |
| Fluoride | MCL | 1 | 1980 |
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 ONIDA.
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 SD4600233 on SDWISSource: EPA SDWIS Federal Reports Search
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 SDWISViolation 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 |
|---|---|---|---|---|
| 2004 | Public Notice | Other | 1 | SDWIS / SD4600233 / 7500 |
| 2003 | Coliform (TCR) | MR | 45 | SDWIS / SD4600233 / 3100 |
| 2002 | Consumer Confidence Rule | Other | 4 | SDWIS / SD4600233 / 7000 |
| 2001 | Lead and Copper Rule | Other | 2 | SDWIS / SD4600233 / 5000 |
| 2000 | Lead and Copper Rule | MR | 9 | SDWIS / SD4600233 / 5000 |
| 1998 | Coliform (TCR) | Other | 13 | SDWIS / SD4600233 / 3100 |
| 1997 | Coliform (TCR) | MCL | 33 | SDWIS / SD4600233 / 3100 |
| 1997 | Combined Radium (-226 and -228) | MCL | 8 | SDWIS / SD4600233 / 4010 |
| 1996 | Combined Radium (-226 and -228) | MR | 5 | SDWIS / SD4600233 / 4010 |
| 1996 | Gross Alpha, Excl. Radon and U | MR | 5 | SDWIS / SD4600233 / 4000 |
| 1993 | Asbestos | MR | 2 | SDWIS / SD4600233 / 1094 |
| 1980 | Fluoride | MCL | 1 | SDWIS / SD4600233 / 1025 |
How ONIDA Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | ONIDA | South Dakota avg | Federal benchmark |
|---|---|---|---|
| Total violations | 139 | 86 | SDWA compliance — any non-zero count is a recorded breach |
| Health-based violations | 42 | 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 | 658 | 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 ONIDA water safe to drink? ▼
How many people does ONIDA serve? ▼
What type of violations does ONIDA have? ▼
Has PFAS been detected in ONIDA water? ▼
What water source does ONIDA use? ▼
Where does this data come from? ▼
Explore PlainWater
Related Data for South Dakota
Read our methodology — how this data is sourced, computed, and verified.