Community Water System · PWS NH1391010
Londonderry
Operator location Nashua, New Hampshire - 0% of 8 violations are health-based (lower-third health share (≤ 1%)); surface water source; 5,380 served per SDWIS.
- 5,380
- People served (this PWS)
- 8
- EPA violations (this PWS)
- 0
- Health-based (this PWS)
- 1 PFAS
- UCMR5 (this PWS)
Londonderry standing, low SDWIS violation third
0% of 8 recorded violations are health-based - lower-third health share (≤ 1%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 0% is lower-third health share (≤ 1%). UCMR5: lower-third PFAS panel (≤ 2 compounds). Population rank #7,376 of 29,740 among systems serving 500+.
The verdict
Londonderry is in the lower third by violation count (8; lower-third violation load (≤ 21 violations)). A low count does not mean the system is unmonitored - monitoring and reporting violations still appear in SDWIS. Population served is large (5,380; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is only 0% - almost all of this trail is monitoring or reporting. UCMR5 detected 1 PFAS compound (lower-third PFAS panel (≤ 2 compounds)).
- #7,376 of 29,740
- Population · /systems
- #31 of 284
- Population · NH
- 8
- Total EPA violations on record
- 0%
- Health-based (MCL / treatment failure)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
1 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
System Details
- System Type
- Community
- Owner Type
- Private
- Connections
- 1,786
- County
- Rockingham
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 8
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| TTHM | MR | 4 | 2013 |
| Total Haloacetic Acids (HAA5) | MR | 4 | 2013 |
Violation Count vs. the National Corpus
Londonderry has 8 recorded EPA violations, 15% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 83% carry more. 0% of this system's own violations are health-based (0 of 8), and it ranks #7,376 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)
8 Among the lowest violation counts fewer violations than 83% 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
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 3 of 116 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFPeA | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 9/11/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHpS | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 9/11/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 9/11/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFDoA | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 9/11/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 9/11/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| NEtFOSAA | 9/11/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFDA | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTrDA | 9/11/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFHxA | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 9/11/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 9/11/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 9Cl-PF3ONS | 9/11/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| ADONA | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 9/11/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFOA | 9/11/2023 | 6.10 ppt | 4.00 ppt | Detected |
| 8:2 FTS | 9/11/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTA | 9/11/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| 6:2 FTS | 9/11/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 9/11/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NMeFOSAA | 9/11/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFMPA | 9/11/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFTA | 7/31/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFTrDA | 7/31/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| NEtFOSAA | 7/31/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 7/31/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFPeS | 6/12/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpA | 6/12/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 6/12/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 6/12/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| ADONA | 6/12/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 6/12/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpS | 6/12/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 6/12/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFOS | 6/12/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOA | 6/12/2023 | 4.30 ppt | 4.00 ppt | Detected |
| PFEESA | 6/12/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 6/12/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 6/12/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 6/12/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 6/12/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFMBA | 6/12/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 6/12/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
Health-based violations on Londonderry
0 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for NH1391010.
Sources: EPA SDWIS
Nationwide peers
8 violations · 5,380 served: nearest cross-state SDWIS matches.
Cross-state systems with similarly light violation ledgers
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
- Mohegan Tribal Utility Authority EPA Region 1 — Tribal Water Systems 8violations
- Hannahville Community EPA Region 5 — Tribal Water Systems 8violations
- Quapaw Downstream Casino & Resort EPA Region 6 — Tribal Water Systems 8violations
- San Ildefonso Totavi EPA Region 6 — Tribal Water Systems 8violations
Cross-state systems with similar served population
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Londonderry
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.