Community Water System · PWS AZ0408040
Epcor - Willow Valley/King Street
Operator location El Mirage, Arizona - larger served population (> 3,309) at 3,408 people served; 121 SDWIS violations on record from groundwater sources.
- 3,408
- People served (this PWS) Larger third of systems
- 121
- EPA violations (this PWS) Upper third of systems
- 11
- Health-based (this PWS) Middle third by health-based share
- No PFAS
- UCMR5 (this PWS) Tested, none detected
Epcor - Willow Valley/King Street standing, high SDWIS violation third
3,408 people served (SDWIS) - larger served population (> 3,309). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 9% is middle-third health share (≤ 23%). UCMR5: UCMR5 tested, none detected. Population rank #9,788 of 29,740 among systems serving 500+.
The verdict
Epcor - Willow Valley/King Street sits in the upper third of the sitemap cohort by violation count (121), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is large (3,408; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 9% (middle-third health share (≤ 23%)). UCMR5 tested this system and reported no PFAS above the minimum reporting level.
- #9,788 of 29,740
- Population · /systems
- #145 of 413
- Population · AZ
- 121
- Total EPA violations on record
- 9%
- 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
- Private
- Connections
- 1,421
- County
- Mohave
- School/Daycare
- No
- MCL Violations
- 11
- Monitoring Violations
- 98
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 27 | 2006 |
| Chlorine | MR | 17 | 2021 |
| TTHM | MR | 8 | 2021 |
| Total Haloacetic Acids (HAA5) | MR | 8 | 2021 |
| Coliform (TCR) | MCL | 7 | 2007 |
| Consumer Confidence Rule | Other | 6 | 2015 |
| Nitrate | MR | 5 | 2006 |
| Chlorite | MR | 4 | 2022 |
| Chlorite | MCL | 3 | 2025 |
| Lead and Copper Rule | MR | 1 | 2002 |
| 1,2,4-Trichlorobenzene | MR | 1 | 2004 |
| cis-1,2-Dichloroethylene | MR | 1 | 2004 |
| Xylenes, Total | MR | 1 | 2004 |
| o-Dichlorobenzene | MR | 1 | 2004 |
| 1,2-Dichloroethane | MR | 1 | 2004 |
| 1,1,1-Trichloroethane | MR | 1 | 2004 |
| Carbon tetrachloride | MR | 1 | 2004 |
| 1,2-Dichloropropane | MR | 1 | 2004 |
| Trichloroethylene | MR | 1 | 2004 |
| Tetrachloroethylene | MR | 1 | 2004 |
| CHLOROBENZENE | MR | 1 | 2004 |
| Benzene | MR | 1 | 2004 |
| Ethylbenzene | MR | 1 | 2004 |
| TTHM | MCL | 1 | 2012 |
| Cadmium | MR | 1 | 1988 |
| Arsenic | MR | 1 | 1988 |
| Mercury | MR | 1 | 1988 |
| p-Dichlorobenzene | MR | 1 | 2004 |
| DICHLOROMETHANE | MR | 1 | 2004 |
| Fluoride | MR | 1 | 1988 |
Violation Count vs. the National Corpus
Epcor - Willow Valley/King Street has 121 recorded EPA violations, 77% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 23% carry more. 9% of this system's own violations are health-based (11 of 121), and it ranks #9,788 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)
121 Higher than most more violations than 77% 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
Epcor - Willow Valley/King Street 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 |
|---|---|---|---|---|
| PFUnA | 6/8/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFOA | 6/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFMBA | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 6/8/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFBS | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 6/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 6/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDA | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| ADONA | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 6/8/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeS | 6/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 6/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| HFPO-DA | 6/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 6/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 6:2 FTS | 6/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 6/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 6/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDoA | 6/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 5/2/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFTrDA | 5/2/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| NEtFOSAA | 5/2/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 5/2/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| HFPO-DA | 11/27/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFPeS | 11/27/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 11/27/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFEESA | 11/27/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 11/27/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 11/27/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFTrDA | 11/27/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| NEtFOSAA | 11/27/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 11/27/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFPeA | 11/27/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 11/27/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 8:2 FTS | 11/27/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 11/27/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 11/27/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 11/27/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHpS | 11/27/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| ADONA | 11/27/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 11/27/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 11/27/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 11/27/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 11/27/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
Population served record for Epcor - Willow Valley/King Street
EPA SDWIS lists 3,408 people served and 1,421 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
121 violations · 3,408 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 Epcor - Willow Valley/King Street
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.