Community Water System · PWS OK2005501
Nichols Hills
Operator location Nichols Hills, Oklahoma - larger served population (> 3,309) at 4,020 people served; 279 SDWIS violations on record from groundwater sources.
- 4,020
- People served (this PWS)
- 279
- EPA violations (this PWS)
- 47
- Health-based (this PWS)
- No PFAS
- UCMR5 (this PWS)
Nichols Hills standing, high SDWIS violation third
4,020 people served (SDWIS) - larger served population (> 3,309). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 17% is middle-third health share (≤ 23%). UCMR5: UCMR5 tested, none detected. Population rank #8,823 of 29,740 among systems serving 500+.
The verdict
Nichols Hills sits in the upper third of the sitemap cohort by violation count (279), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is large (4,020; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 17% (middle-third health share (≤ 23%)). UCMR5 tested this system and reported no PFAS above the minimum reporting level.
- #8,823 of 29,740
- Population · /systems
- #121 of 558
- Population · OK
- 279
- Total EPA violations on record
- 17%
- 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
- 1,924
- County
- Oklahoma
- School/Daycare
- No
- MCL Violations
- 45
- Monitoring Violations
- 212
- Treatment Tech Violations
- 2
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MCL | 14 | 2008 |
| Nitrate-Nitrite | MR | 12 | 2024 |
| Combined Uranium | MCL | 9 | 2005 |
| Arsenic | MCL | 8 | 2016 |
| Selenium | MCL | 7 | 2000 |
| Gross Alpha, Excl. Radon and U | MCL | 7 | 2004 |
| Total Haloacetic Acids (HAA5) | MR | 6 | 2025 |
| TTHM | MR | 6 | 2025 |
| BHC-GAMMA | MR | 6 | 2024 |
| Methoxychlor | MR | 6 | 2024 |
| Dalapon | MR | 6 | 2024 |
| Diquat | MR | 6 | 2024 |
| Glyphosate | MR | 6 | 2024 |
| Di(2-ethylhexyl) adipate | MR | 6 | 2024 |
| Simazine | MR | 6 | 2024 |
| Di(2-ethylhexyl) phthalate | MR | 6 | 2024 |
| Picloram | MR | 6 | 2024 |
| Hexachlorocyclopentadiene | MR | 6 | 2024 |
| Atrazine | MR | 6 | 2024 |
| Heptachlor | MR | 6 | 2024 |
| 2,4,5-TP | MR | 6 | 2024 |
| HEXACHLOROBENZENE | MR | 6 | 2024 |
| Pentachlorophenol | MR | 6 | 2024 |
| Total Polychlorinated Biphenyls (PCB) | MR | 6 | 2024 |
| ETHYLENE DIBROMIDE | MR | 6 | 2024 |
| Chlordane | MR | 6 | 2024 |
| Endrin | MR | 6 | 2024 |
| Toxaphene | MR | 6 | 2024 |
| Endothall | MR | 6 | 2024 |
| Carbofuran | MR | 6 | 2024 |
Violation Count vs. the National Corpus
Nichols Hills has 279 recorded EPA violations, 90% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 10% carry more. 17% of this system's own violations are health-based (47 of 279), and it ranks #8,823 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)
279 Higher than most more violations than 90% 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 87 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFTA | 9/9/2025 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFDoA | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 9/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 9/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFNA | 9/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxS | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| NMeFOSAA | 9/9/2025 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFTrDA | 9/9/2025 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFUnA | 9/9/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFBS | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| NEtFOSAA | 9/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMBA | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpS | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 9/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 9/9/2025 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFEESA | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 9/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| 8:2 FTS | 9/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 6:2 FTS | 9/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 9/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| HFPO-DA | 9/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| ADONA | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 9/9/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| 4:2 FTS | 9/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 9/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| ADONA | 7/8/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 7/8/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 7/8/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 7/8/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 7/8/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 7/8/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 9Cl-PF3ONS | 7/8/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFDoA | 7/8/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 7/8/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 7/8/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpA | 7/8/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 7/8/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFOA | 7/8/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDA | 7/8/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 7/8/2024 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFOS | 7/8/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeS | 7/8/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 7/8/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 7/8/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFEESA | 7/8/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 7/8/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
Population served record for Nichols Hills
EPA SDWIS lists 4,020 people served and 1,924 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
279 violations · 4,020 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 Nichols Hills
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Oklahoma compares on the same EPA violation measures. Oklahoma 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.