Non-Transient Non-Community Water System · PWS 090400701
San Carlos High School
Operator location San Carlos, EPA Region 9 — Tribal Water Systems - smaller served population (≤ 999) at 626 people served; 208 SDWIS violations on record from groundwater sources.
- 626
- People served (this PWS)
- 208
- EPA violations (this PWS)
- 5
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
San Carlos High School standing, high SDWIS violation third
626 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 2% is middle-third health share (≤ 23%). Population rank #25,672 of 29,740 among systems serving 500+.
The verdict
San Carlos High School sits in the upper third of the sitemap cohort by violation count (208), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is smaller (626; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 2% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- #25,672 of 29,740
- Population · /systems
- #113 of 129
- Population · 09
- 208
- Total EPA violations on record
- 2%
- 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
- 9
- School/Daycare
- Yes
- MCL Violations
- 5
- Monitoring Violations
- 174
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 49 | 2010 |
| Nitrate | MR | 10 | 2022 |
| Chlorine | MR | 8 | 2024 |
| Total Haloacetic Acids (HAA5) | MR | 8 | 2024 |
| TTHM | MR | 8 | 2024 |
| Coliform (TCR) | MCL | 5 | 2013 |
| Lead and Copper Rule | MR | 5 | 2010 |
| Arsenic | MR | 3 | 2020 |
| Revised Total Coliform Rule | MON | 3 | 2024 |
| Public Notice | Other | 3 | 2024 |
| Cadmium | MR | 2 | 2001 |
| Chromium | MR | 2 | 2001 |
| CYANIDE | MR | 2 | 2001 |
| Selenium | MR | 2 | 2001 |
| Endrin | MR | 2 | 2001 |
| BHC-GAMMA | MR | 2 | 2001 |
| Methoxychlor | MR | 2 | 2001 |
| Dalapon | MR | 2 | 2001 |
| Toxaphene | MR | 2 | 2001 |
| Thallium, Total | MR | 2 | 2001 |
| Asbestos | MR | 2 | 2001 |
| Antimony, Total | MR | 2 | 2001 |
| Beryllium, Total | MR | 2 | 2001 |
| Mercury | MR | 2 | 2001 |
| Fluoride | MR | 2 | 2001 |
| Barium | MR | 2 | 2001 |
| Glyphosate | MR | 1 | 2001 |
| Di(2-ethylhexyl) phthalate | MR | 1 | 2001 |
| Picloram | MR | 1 | 2001 |
| Dinoseb | MR | 1 | 2001 |
Violation Count vs. the National Corpus
San Carlos High School has 208 recorded EPA violations, 86% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 14% carry more. 2% of this system's own violations are health-based (5 of 208), and it ranks #25,672 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)
208 Higher than most more violations than 86% 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 San Carlos High School
EPA SDWIS lists 626 people served and 9 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
208 violations · 626 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 with smaller service footprints
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with San Carlos High School
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in EPA Region 9 — Tribal Water Systems compares on the same EPA violation measures. EPA Region 9 — Tribal Water Systems 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.