Community Water System · PWS NH1141020
Emerald Lake
Operator location Hillsboro, New Hampshire - 72% of 179 violations are health-based (upper-third health share (> 23%)); groundwater source; 1,300 served per SDWIS.
- 1,300
- People served (this PWS)
- 179
- EPA violations (this PWS)
- 129
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Emerald Lake standing, high SDWIS violation third
72% of 179 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 72% is upper-third health share (> 23%). Population rank #17,161 of 29,740 among systems serving 500+.
The verdict
Emerald Lake sits in the upper third of the sitemap cohort by violation count (179), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is mid-pack at 1,300 (mid served population (≤ 3,309)). Health-based share is 72% - most of this ledger is MCL or treatment-technique exceedance. No UCMR5 PFAS test appears for this system in this extract.
- #17,161 of 29,740
- Population · /systems
- #94 of 284
- Population · NH
- 179
- Total EPA violations on record
- 72%
- 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
- Community
- Owner Type
- Local
- Connections
- 528
- County
- Hillsborough
- School/Daycare
- No
- MCL Violations
- 122
- Monitoring Violations
- 22
- Treatment Tech Violations
- 7
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Arsenic | MCL | 64 | 2020 |
| Coliform (TCR) | MCL | 30 | 2013 |
| Fluoride | MCL | 28 | 2011 |
| Public Notice | Other | 17 | 2020 |
| Consumer Confidence Rule | Other | 7 | 2016 |
| Groundwater Rule | TT | 7 | 2020 |
| Revised Total Coliform Rule | MON | 4 | 2021 |
| Revised Total Coliform Rule | RPT | 4 | 2021 |
| TTHM | MR | 4 | 2024 |
| Total Haloacetic Acids (HAA5) | MR | 4 | 2024 |
| Fluoride | MR | 3 | 2007 |
| Arsenic | MR | 3 | 2007 |
| E. COLI | MR | 2 | 2016 |
| Lead and Copper Rule | MR | 2 | 1995 |
Violation Count vs. the National Corpus
Emerald Lake has 179 recorded EPA violations, 84% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 16% carry more. 72% of this system's own violations are health-based (129 of 179), and it ranks #17,161 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)
179 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
Health-based violations on Emerald Lake
129 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for NH1141020.
Sources: EPA SDWIS
Nationwide peers
179 violations · 1,300 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.
Cross-state systems near this population served
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Emerald Lake
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in New Hampshire compares on the same EPA violation measures. New Hampshire 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.