Non-Transient Non-Community Water System · PWS MA2115010
Groton Dunstable Reg. H.s.
Operator location Groton, Massachusetts - 24% of 33 violations are health-based (upper-third health share (> 23%)); groundwater source; 940 served per SDWIS.
- 940
- People served (this PWS)
- 33
- EPA violations (this PWS)
- 8
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Groton Dunstable Reg. H.s. standing, mid SDWIS violation third
24% of 33 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 24% is upper-third health share (> 23%). Population rank #20,542 of 29,740 among systems serving 500+.
The verdict
Groton Dunstable Reg. H.s. lands in the middle third by violation volume (33), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is smaller (940; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 24% - most of this ledger is MCL or treatment-technique exceedance. No UCMR5 PFAS test appears for this system in this extract.
- #20,542 of 29,740
- Population · /systems
- #340 of 418
- Population · MA
- 33
- Total EPA violations on record
- 24%
- Health-based (MCL / treatment failure)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
System Details
- System Type
- Non-Transient Non-Community
- Owner Type
- Local
- Connections
- 1
- County
- Middlesex
- School/Daycare
- Yes
- MCL Violations
- 8
- Monitoring Violations
- 12
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MCL | 8 | 2015 |
| Coliform (TCR) | MR | 6 | 2003 |
| Radium-228 | MR | 2 | 2004 |
| Lead and Copper Rule | MR | 2 | 2007 |
| Radium-226 | MR | 2 | 2004 |
Violation Count vs. the National Corpus
Groton Dunstable Reg. H.s. has 33 recorded EPA violations, 45% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 54% carry more. 24% of this system's own violations are health-based (8 of 33), and it ranks #20,542 of 29,740 by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
33 Lower than most fewer violations than 54% 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
Health-based violations on Groton Dunstable Reg. H.s.
8 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for MA2115010.
Sources: EPA SDWIS · MassDEP, Drinking Water Program
Nationwide peers
33 violations · 940 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.
Cross-state systems with smaller service footprints
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Groton Dunstable Reg. H.s.
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Massachusetts compares on the same EPA violation measures. Massachusetts 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.