Community Water System · PWS CA3610031
Muscoy MWC No. 1
Operator location San Bernardino, California - larger served population (> 3,309) at 13,000 people served; 45 SDWIS violations on record from groundwater sources.
- 13,000
- People served (this PWS)
- 45
- EPA violations (this PWS)
- 6
- Health-based (this PWS)
- No PFAS
- UCMR5 (this PWS)
Muscoy MWC No. 1 standing, mid SDWIS violation third
13,000 people served (SDWIS) - larger served population (> 3,309). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 13% is middle-third health share (≤ 23%). UCMR5: UCMR5 tested, none detected. Population rank #3,859 of 29,740 among systems serving 500+.
The verdict
Muscoy MWC No. 1 lands in the middle third by violation volume (45), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is large (13,000; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 13% (middle-third health share (≤ 23%)). UCMR5 tested this system and reported no PFAS above the minimum reporting level.
- #3,859 of 29,740
- Population · /systems
- #430 of 1,701
- Population · CA
- 45
- Total EPA violations on record
- 13%
- 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
- Private
- Connections
- 1,459
- County
- San Bernardino
- School/Daycare
- No
- MCL Violations
- 6
- Monitoring Violations
- 36
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Revised Total Coliform Rule | MON | 32 | 2024 |
| Coliform (TCR) | MCL | 6 | 2009 |
| Coliform (TCR) | MR | 4 | 2012 |
Violation Count vs. the National Corpus
Muscoy MWC No. 1 has 45 recorded EPA violations, 54% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 46% carry more. 13% of this system's own violations are health-based (6 of 45), and it ranks #3,859 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)
45 Around the middle fewer violations than 46% 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. 0 of 58 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| NEtFOSAA | 8/12/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 8/12/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 8/12/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeA | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 8/12/2024 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeS | 8/12/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 8/12/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 8/12/2024 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFOS | 8/12/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFTA | 8/12/2024 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFBA | 8/12/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| HFPO-DA | 8/12/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| ADONA | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 8/12/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 8/12/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 8/12/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFDA | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 8/12/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxS | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NMeFOSAA | 8/12/2024 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFDoA | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 8/12/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 8/12/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFEESA | 2/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 2/22/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| ADONA | 2/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 2/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 2/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 6:2 FTS | 2/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 2/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 2/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 2/22/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFMBA | 2/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpS | 2/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 2/22/2024 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeS | 2/22/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 2/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTA | 2/22/2024 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFPeA | 2/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 2/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NEtFOSAA | 2/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 2/22/2024 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFUnA | 2/22/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHpA | 2/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
Population served record for Muscoy MWC No. 1
EPA SDWIS lists 13,000 people served and 1,459 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS · California State Water Resources Control Board, Division of Drinking Water
Nationwide peers
45 violations · 13,000 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 similar served population
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Muscoy MWC No. 1
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.