Community Water System · PWS SD4600316
Walnut Park
Spearfish, South Dakota 57783 - drinking water served from groundwater sources to 180 people, tracked in EPA SDWIS and UCMR5.
- 180
- People served
- 219
- EPA violations
- 20
- Health-based
- Untested
- UCMR5 result
The verdict
EPA records 219 drinking-water violations at Walnut Park, 9% of them health-based - above the South Dakota per-system average.
- 219
- Total EPA violations on record
- 9%
- Health-based (MCL / treatment failure)
- 180
- People served by this system
- N/A
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: Walnut Park
Walnut Park is a private-owned community water system that delivers drinking water to 180 residents in Spearfish, South Dakota (Lawrence County) through 72 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 219 total violations for this system , of which 20 (9%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 177 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.
The most frequently cited contaminant at this system is Chlorine, recorded in 40 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. Statewide, 42 of 49 UCMR5-tested systems have reported PFAS detections (85.7%).
Walnut Park's 219 violations sit above the South Dakota average.
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
- Private
- Connections
- 72
- County
- Lawrence
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 177
- Treatment Tech Violations
- 20
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Chlorine | MR | 40 | 2018 |
| Stage 1 Disinfectants and Disinfection Byproducts Rule | TT | 14 | 2019 |
| Arsenic | MR | 13 | 2006 |
| Public Notice | Other | 13 | 2007 |
| Lead and Copper Rule | MR | 9 | 2006 |
| Total Haloacetic Acids (HAA5) | MR | 5 | 2006 |
| TTHM | MR | 5 | 2006 |
| Coliform (TCR) | MR | 4 | 2013 |
| Groundwater Rule | TT | 4 | 2018 |
| Revised Total Coliform Rule | MON | 3 | 2018 |
| LASSO | MR | 3 | 1993 |
| Total Polychlorinated Biphenyls (PCB) | MR | 3 | 1993 |
| Di(2-ethylhexyl) phthalate | MR | 3 | 1993 |
| Hexachlorocyclopentadiene | MR | 3 | 1993 |
| HEXACHLOROBENZENE | MR | 3 | 1993 |
| BHC-GAMMA | MR | 3 | 1993 |
| Aldicarb | MR | 3 | 1993 |
| Aldicarb sulfone | MR | 3 | 1993 |
| Carbofuran | MR | 3 | 1993 |
| Dinoseb | MR | 3 | 1993 |
| Pentachlorophenol | MR | 3 | 1993 |
| 2,4-D | MR | 3 | 1993 |
| ETHYLENE DIBROMIDE | MR | 3 | 1993 |
| Endothall | MR | 3 | 1993 |
| Glyphosate | MR | 3 | 1993 |
| Di(2-ethylhexyl) adipate | MR | 3 | 1993 |
| Endrin | MR | 3 | 1993 |
| 1,2-DIBROMO-3-CHLOROPROPANE | MR | 3 | 1993 |
| OXAMYL | MR | 3 | 1993 |
| 2,4,5-TP | MR | 3 | 1993 |
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 Walnut Park.
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 SD4600316 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 |
|---|---|---|---|---|
| 2024 | LEAD AND COPPER RULE REVISIONS | RPT | 2 | SDWIS / SD4600316 / 5200 |
| 2024 | LEAD AND COPPER RULE REVISIONS | TT | 2 | SDWIS / SD4600316 / 5200 |
| 2019 | Stage 1 Disinfectants and Disinfection Byproducts Rule | TT | 14 | SDWIS / SD4600316 / 0400 |
| 2018 | Chlorine | MR | 40 | SDWIS / SD4600316 / 0999 |
| 2018 | Groundwater Rule | TT | 4 | SDWIS / SD4600316 / 0700 |
| 2018 | Revised Total Coliform Rule | MON | 3 | SDWIS / SD4600316 / 8000 |
| 2013 | Coliform (TCR) | MR | 4 | SDWIS / SD4600316 / 3100 |
| 2007 | Public Notice | Other | 13 | SDWIS / SD4600316 / 7500 |
| 2006 | Arsenic | MR | 13 | SDWIS / SD4600316 / 1005 |
| 2006 | Lead and Copper Rule | MR | 9 | SDWIS / SD4600316 / 5000 |
| 2006 | Total Haloacetic Acids (HAA5) | MR | 5 | SDWIS / SD4600316 / 2456 |
| 2006 | TTHM | MR | 5 | SDWIS / SD4600316 / 2950 |
| 2000 | Consumer Confidence Rule | Other | 2 | SDWIS / SD4600316 / 7000 |
| 1993 | LASSO | MR | 3 | SDWIS / SD4600316 / 2051 |
| 1993 | Total Polychlorinated Biphenyls (PCB) | MR | 3 | SDWIS / SD4600316 / 2383 |
How Walnut Park Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | Walnut Park | South Dakota avg | Federal benchmark |
|---|---|---|---|
| Total violations | 219 | 86 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 20 | 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 | 180 | 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 (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 Walnut Park water safe to drink? ▼
How many people does Walnut Park serve? ▼
What type of violations does Walnut Park have? ▼
Has PFAS been detected in Walnut Park water? ▼
What water source does Walnut Park use? ▼
Where does this data come from? ▼
Read our methodology - how this data is sourced, computed, and verified.
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.