Non-Transient Non-Community Water System · PWS CA3710707
Usn San Clemente Island
Operator location San Diego, California - 88% of 57 violations are health-based (upper-third health share (> 23%)); surface water source; 800 served per SDWIS.
- 800
- People served (this PWS)
- 57
- EPA violations (this PWS)
- 50
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Usn San Clemente Island standing, mid SDWIS violation third
88% of 57 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 88% is upper-third health share (> 23%). Population rank #22,398 of 29,740 among systems serving 500+.
The verdict
Usn San Clemente Island lands in the middle third by violation volume (57), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is smaller (800; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 88% - most of this ledger is MCL or treatment-technique exceedance. No UCMR5 PFAS test appears for this system in this extract.
- #22,398 of 29,740
- Population · /systems
- #1,330 of 1,701
- Population · CA
- 57
- Total EPA violations on record
- 88%
- 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
- Federal
- Connections
- 221
- County
- San Diego
- School/Daycare
- No
- MCL Violations
- 46
- Monitoring Violations
- 7
- Treatment Tech Violations
- 4
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| TTHM | MCL | 45 | 2014 |
| Coliform (TCR) | MR | 5 | 2011 |
| Surface Water Treatment Rule | TT | 4 | 2025 |
| Revised Total Coliform Rule | MON | 2 | 2025 |
| Total Haloacetic Acids (HAA5) | MCL | 1 | 2024 |
Violation Count vs. the National Corpus
Usn San Clemente Island has 57 recorded EPA violations, 60% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 40% carry more. 88% of this system's own violations are health-based (50 of 57), and it ranks #22,398 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)
57 Around the middle fewer violations than 40% 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 Usn San Clemente Island
50 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for CA3710707.
Sources: EPA SDWIS · California State Water Resources Control Board, Division of Drinking Water
Nationwide peers
57 violations · 800 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 Usn San Clemente Island
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in California compares on the same EPA violation measures. California 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.