Community Water System · PWS SD4600154
Hermosa-Old System
Operator location Hermosa, South Dakota - smaller served population (≤ 999) at 420 people served; 37 SDWIS violations on record from groundwater sources.
- 420
- People served (this PWS)
- 37
- EPA violations (this PWS)
- 2
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Hermosa-Old System standing, mid SDWIS violation third
420 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 5% is middle-third health share (≤ 23%).
The verdict
Hermosa-Old System lands in the middle third by violation volume (37), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is smaller (420; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 5% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- 37
- Total EPA violations on record
- 5%
- Health-based (MCL / treatment failure)
- 420
- 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
- 277
- County
- Custer
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 24
- Treatment Tech Violations
- 2
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Chlorine | MR | 10 | 2006 |
| Coliform (TCR) | MR | 4 | 1995 |
| Combined Radium (-226 and -228) | MR | 3 | 2021 |
| Gross Alpha, Excl. Radon and U | MR | 3 | 2021 |
| Stage 1 Disinfectants and Disinfection Byproducts Rule | TT | 2 | 2010 |
| Combined Uranium | MR | 2 | 2021 |
| Revised Total Coliform Rule | MON | 2 | 2025 |
| Consumer Confidence Rule | Other | 2 | 2004 |
Violation Count vs. the National Corpus
Hermosa-Old System has 37 recorded EPA violations, 48% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 51% carry more. 5% of this system's own violations are health-based (2 of 37), 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)
37 Lower than most fewer violations than 51% 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 Hermosa-Old System
EPA SDWIS lists 420 people served and 277 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
37 violations · 420 served: nearest cross-state SDWIS matches.
Cross-state systems near this violation count
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
What to do with Hermosa-Old System
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.