Community Water System · PWS SD4600287
Saint Onge Sewer & Water Co
Operator location Spearfish, South Dakota - smaller served population (≤ 999) at 255 people served; 185 SDWIS violations on record from groundwater sources.
- 255
- People served (this PWS)
- 185
- EPA violations (this PWS)
- 24
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Saint Onge Sewer & Water Co standing, high SDWIS violation third
255 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 13% is middle-third health share (≤ 23%).
The verdict
Saint Onge Sewer & Water Co sits in the upper third of the sitemap cohort by violation count (185), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is smaller (255; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 13% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- 185
- Total EPA violations on record
- 13%
- Health-based (MCL / treatment failure)
- 255
- People served by this PWS (SDWIS)
- N/A
- PFAS compounds detected (UCMR5)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 85
- County
- Lawrence
- School/Daycare
- No
- MCL Violations
- 24
- Monitoring Violations
- 155
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MCL | 24 | 2006 |
| Lead and Copper Rule | MR | 7 | 1995 |
| Coliform (TCR) | MR | 6 | 1999 |
| LASSO | MR | 3 | 1993 |
| Heptachlor | MR | 3 | 1993 |
| Heptachlor epoxide | MR | 3 | 1993 |
| Atrazine | MR | 3 | 1993 |
| Benzo(a)pyrene | MR | 3 | 1993 |
| Total Polychlorinated Biphenyls (PCB) | MR | 3 | 1993 |
| Hexachlorocyclopentadiene | MR | 3 | 1993 |
| Endrin | MR | 3 | 1993 |
| HEXACHLOROBENZENE | MR | 3 | 1993 |
| Chlordane | MR | 3 | 1993 |
| Toxaphene | MR | 3 | 1993 |
| Aldicarb | MR | 3 | 1993 |
| Aldicarb sulfone | MR | 3 | 1993 |
| Dalapon | MR | 3 | 1993 |
| Dinoseb | MR | 3 | 1993 |
| 2,4,5-TP | MR | 3 | 1993 |
| Picloram | MR | 3 | 1993 |
| 2,4-D | MR | 3 | 1993 |
| 1,2-DIBROMO-3-CHLOROPROPANE | MR | 3 | 1993 |
| Endothall | MR | 3 | 1993 |
| Glyphosate | MR | 3 | 1993 |
| Diquat | MR | 3 | 1993 |
| BHC-GAMMA | MR | 3 | 1993 |
| Carbofuran | MR | 3 | 1993 |
| Di(2-ethylhexyl) phthalate | MR | 3 | 1993 |
| Simazine | MR | 3 | 1993 |
| OXAMYL | MR | 3 | 1993 |
Violation Count vs. the National Corpus
Saint Onge Sewer & Water Co has 185 recorded EPA violations, 84% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 16% carry more. 13% of this system's own violations are health-based (24 of 185), and it ranks unranked by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
185 Higher than most more violations than 84% of 29,740 water systems
the national water-system corpus, bucketed by value
Each bar is a band; taller bars hold more water systems. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA SDWIS · 2026-05-15
Population served record for Saint Onge Sewer & Water Co
EPA SDWIS lists 255 people served and 85 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
185 violations · 255 served: nearest cross-state SDWIS matches.
Cross-state systems with comparable violation load
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
What to do with Saint Onge Sewer & Water Co
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in South Dakota compares on the same EPA violation measures. South Dakota systems
- Check whether PFAS was detected at this system under UCMR5 testing. PFAS guide
- Find and compare another public water system by name or PWSID. Search systems
EPA SDWIS and UCMR5 figures are informational only, not a substitute for a certified lab test of your own tap water.