Community Water System · PWS AZ0401012
St Johns City Of
Operator location Saint Johns, Arizona - larger served population (> 3,309) at 3,500 people served; 263 SDWIS violations on record from groundwater sources.
- 3,500
- People served (this PWS) Larger third of systems
- 263
- EPA violations (this PWS) Upper third of systems
- 8
- Health-based (this PWS) Middle third by health-based share
- No PFAS
- UCMR5 (this PWS) Tested, none detected
St Johns City Of standing, high SDWIS violation third
3,500 people served (SDWIS) - larger served population (> 3,309). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 3% is middle-third health share (≤ 23%). UCMR5: UCMR5 tested, none detected. Population rank #9,612 of 29,740 among systems serving 500+.
The verdict
St Johns City Of sits in the upper third of the sitemap cohort by violation count (263), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is large (3,500; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 3% (middle-third health share (≤ 23%)). UCMR5 tested this system and reported no PFAS above the minimum reporting level.
- #9,612 of 29,740
- Population · /systems
- #141 of 413
- Population · AZ
- 263
- Total EPA violations on record
- 3%
- Health-based (MCL / treatment failure)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
Based on EPA SDWIS violation history and UCMR5 PFAS testing only, not water taste, odor, infrastructure age, or contaminants outside the federally tracked set.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 1,275
- County
- Apache
- School/Daycare
- No
- MCL Violations
- 8
- Monitoring Violations
- 199
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Combined Radium (-226 and -228) | MR | 40 | 2025 |
| Chlorine | MR | 30 | 2022 |
| Consumer Confidence Rule | Other | 27 | 2025 |
| Lead and Copper Rule | MR | 10 | 2023 |
| TTHM | MR | 8 | 2025 |
| Total Haloacetic Acids (HAA5) | MR | 8 | 2025 |
| Coliform (TCR) | MCL | 4 | 2013 |
| Nitrate | MR | 4 | 2006 |
| Revised Total Coliform Rule | RPT | 4 | 2020 |
| Gross Alpha, Excl. Radon and U | MR | 3 | 2004 |
| Coliform (TCR) | MR | 3 | 2008 |
| DICHLOROMETHANE | MR | 3 | 2002 |
| o-Dichlorobenzene | MR | 3 | 2002 |
| 1,2-Dichloropropane | MR | 3 | 2002 |
| Styrene | MR | 3 | 2002 |
| cis-1,2-Dichloroethylene | MR | 3 | 2002 |
| trans-1,2-Dichloroethylene | MR | 3 | 2002 |
| Tetrachloroethylene | MR | 3 | 2002 |
| 1,1,2-Trichloroethane | MR | 3 | 2002 |
| Toluene | MR | 3 | 2002 |
| Combined Radium (-226 and -228) | MCL | 3 | 2001 |
| Ethylbenzene | MR | 3 | 2002 |
| CHLOROBENZENE | MR | 3 | 2002 |
| Revised Total Coliform Rule | MON | 2 | 2018 |
| 1,2,4-Trichlorobenzene | MR | 2 | 2002 |
| p-Dichlorobenzene | MR | 2 | 2002 |
| Carbon tetrachloride | MR | 2 | 2002 |
| Benzene | MR | 2 | 2002 |
| Xylenes, Total | MR | 2 | 2002 |
| 1,1-Dichloroethylene | MR | 2 | 2002 |
Violation Count vs. the National Corpus
St Johns City Of has 263 recorded EPA violations, 89% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 11% carry more. 3% of this system's own violations are health-based (8 of 263), and it ranks #9,612 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)
263 Higher than most more violations than 89% 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
How many violations vs. how serious, among peer systems
St Johns City Of plotted against 29 peer public water systems (500+ people served), by total violation count (x) and the share of those violations that are health-based (y). The crosshair sits at this sample's own median on each axis. A high violation count does not automatically mean a serious record: most monitoring and reporting violations are minor, not health-based.
Violation volume vs. health-based share
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 58 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFBA | 5/13/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 6:2 FTS | 5/13/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFEESA | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 5/13/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 5/13/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeA | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 5/13/2024 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeS | 5/13/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 4:2 FTS | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 5/13/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHpA | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NEtFOSAA | 5/13/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFNA | 5/13/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFTrDA | 5/13/2024 | <7.00 ppt | 7.00 ppt | Not Detected |
| ADONA | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NMeFOSAA | 5/13/2024 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFTA | 5/13/2024 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFBS | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOS | 5/13/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOA | 5/13/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDA | 5/13/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 5/13/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 5/13/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 9Cl-PF3ONS | 5/13/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFTrDA | 11/19/2024 | <7.00 ppt | 7.00 ppt | Not Detected |
| 6:2 FTS | 11/19/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 11/19/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 11/19/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFPeA | 11/19/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 11/19/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 11/19/2024 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeS | 11/19/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| NMeFOSAA | 11/19/2024 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFTA | 11/19/2024 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFBA | 11/19/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| NEtFOSAA | 11/19/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 11/19/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 11/19/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 11/19/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 11/19/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMBA | 11/19/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 11/19/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 11/19/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 11/19/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 11/19/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
Population served record for St Johns City Of
EPA SDWIS lists 3,500 people served and 1,275 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS · Arizona DEQ, Drinking Water Program
Nationwide peers
263 violations · 3,500 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 similar served population
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with St Johns City Of
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Arizona compares on the same EPA violation measures. Arizona 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.
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.