Community Water System · PWS AZ0403026
Williams City Of
Operator location Williams, Arizona - upper-third violation load (> 74 violations) with 314 EPA violations; groundwater source; 3,145 served (PWS-level, not municipal population).
- 3,145
- People served (this PWS)
- 314
- EPA violations (this PWS)
- 23
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Williams City Of standing, high SDWIS violation third
314 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 7% is middle-third health share (≤ 23%). Population rank #10,290 of 29,740 among systems serving 500+.
The verdict
Williams City Of sits in the upper third of the sitemap cohort by violation count (314), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is mid-pack at 3,145 (mid served population (≤ 3,309)). Health-based share is 7% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- #10,290 of 29,740
- Population · /systems
- #151 of 413
- Population · AZ
- 314
- Total EPA violations on record
- 7%
- 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
- Local
- Connections
- 1,883
- County
- Coconino
- School/Daycare
- No
- MCL Violations
- 6
- Monitoring Violations
- 248
- Treatment Tech Violations
- 17
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Chlorine | MR | 30 | 2025 |
| Coliform (TCR) | MR | 28 | 2015 |
| Interim Enhanced Surface Water Treatment Rule | MR | 21 | 2022 |
| Consumer Confidence Rule | Other | 20 | 2025 |
| TTHM | MR | 19 | 2016 |
| Total Haloacetic Acids (HAA5) | MR | 19 | 2012 |
| Surface Water Treatment Rule | MR | 16 | 2022 |
| E. COLI | MR | 16 | 2018 |
| Interim Enhanced Surface Water Treatment Rule | TT | 11 | 2023 |
| Public Notice | Other | 6 | 2023 |
| CARBON, TOTAL | TT | 6 | 2022 |
| TTHM | MCL | 4 | 2006 |
| Lead and Copper Rule | MR | 4 | 2021 |
| CARBON, TOTAL | MR | 4 | 2023 |
| cis-1,2-Dichloroethylene | MR | 3 | 1999 |
| o-Dichlorobenzene | MR | 3 | 1999 |
| p-Dichlorobenzene | MR | 3 | 1999 |
| 1,2-Dichloroethane | MR | 3 | 1999 |
| 2,4-D | MR | 3 | 1999 |
| DICHLOROMETHANE | MR | 3 | 1999 |
| 1,1-Dichloroethylene | MR | 3 | 1999 |
| 1,1,1-Trichloroethane | MR | 3 | 1999 |
| Carbon tetrachloride | MR | 3 | 1999 |
| CHLOROBENZENE | MR | 3 | 1999 |
| Benzene | MR | 3 | 1999 |
| Styrene | MR | 3 | 1999 |
| 1,2-Dichloropropane | MR | 3 | 1999 |
| Trichloroethylene | MR | 3 | 1999 |
| 1,1,2-Trichloroethane | MR | 3 | 1999 |
| trans-1,2-Dichloroethylene | MR | 3 | 1999 |
Violation Count vs. the National Corpus
Williams City Of has 314 recorded EPA violations, 91% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 9% carry more. 7% of this system's own violations are health-based (23 of 314), and it ranks #10,290 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)
314 Higher than most more violations than 91% 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 Williams City Of
314 violations on record for AZ0403026; use EPA SDWIS to confirm return-to-compliance dates and monitoring categories.
Sources: EPA SDWIS · Arizona DEQ, Drinking Water Program
Nationwide peers
314 violations · 3,145 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 Williams 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.