Community Water System · PWS 090400110
SCUA Bylas
Operator location San Carlos, EPA Region 9 — Tribal Water Systems - upper-third violation load (> 74 violations) with 516 EPA violations; groundwater source; 3,160 served (PWS-level, not municipal population).
- 3,160
- People served (this PWS)
- 516
- EPA violations (this PWS)
- 77
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
SCUA Bylas standing, high SDWIS violation third
516 EPA SDWIS violations on record - upper-third violation load (> 74 violations). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 15% is middle-third health share (≤ 23%). Population rank #10,247 of 29,740 among systems serving 500+.
The verdict
SCUA Bylas sits in the upper third of the sitemap cohort by violation count (516), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is mid-pack at 3,160 (mid served population (≤ 3,309)). Health-based share is 15% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- #10,247 of 29,740
- Population · /systems
- #42 of 129
- Population · 09
- 516
- Total EPA violations on record
- 15%
- 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
- Native American
- Connections
- 573
- School/Daycare
- No
- MCL Violations
- 59
- Monitoring Violations
- 345
- Treatment Tech Violations
- 18
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 114 | 2015 |
| Coliform (TCR) | MCL | 55 | 2014 |
| Consumer Confidence Rule | Other | 16 | 2022 |
| Public Notice | Other | 16 | 2023 |
| Revised Total Coliform Rule | RPT | 14 | 2023 |
| Groundwater Rule | TT | 12 | 2023 |
| E. COLI | MR | 10 | 2018 |
| Chlorine | MR | 7 | 2025 |
| Nitrate | MR | 5 | 2010 |
| Total Polychlorinated Biphenyls (PCB) | MR | 5 | 2008 |
| 1,2-DIBROMO-3-CHLOROPROPANE | MR | 5 | 2008 |
| Arsenic | MR | 4 | 2008 |
| Cadmium | MR | 4 | 2008 |
| Barium | MR | 4 | 2008 |
| Chromium | MR | 4 | 2008 |
| Mercury | MR | 4 | 2008 |
| Selenium | MR | 4 | 2008 |
| BHC-GAMMA | MR | 4 | 2008 |
| Toxaphene | MR | 4 | 2008 |
| Methoxychlor | MR | 4 | 2008 |
| Carbofuran | MR | 4 | 2008 |
| Atrazine | MR | 4 | 2008 |
| LASSO | MR | 4 | 2008 |
| Heptachlor | MR | 4 | 2008 |
| Heptachlor epoxide | MR | 4 | 2008 |
| 2,4-D | MR | 4 | 2008 |
| 2,4,5-TP | MR | 4 | 2008 |
| Pentachlorophenol | MR | 4 | 2008 |
| Chlordane | MR | 4 | 2008 |
| Revised Total Coliform Rule | MCL | 4 | 2024 |
Violation Count vs. the National Corpus
SCUA Bylas has 516 recorded EPA violations, 96% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 4% carry more. 15% of this system's own violations are health-based (77 of 516), and it ranks #10,247 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)
516 Higher than most more violations than 96% 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
SDWIS compliance record for SCUA Bylas
516 violations on record for 090400110; use EPA SDWIS to confirm return-to-compliance dates and monitoring categories.
Sources: EPA SDWIS
Nationwide peers
516 violations · 3,160 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 SCUA Bylas
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.