Public water system record
Grand Lake PWA
Serves an area of Delaware County, OK · 2,800 people served
Federal records show 3 health-based violations and 15 monitoring/reporting issues for Grand Lake PWA in the last ten years. The most serious issue in this window was a Combined Radium (-226 and -228) violation that EPA lists as archived, not resolved.
System profile
Source water
Groundwater
ZIP
74051
EPA system ID
OK1021691
- Health-based violations, last 10 years
- 3
- Resolved
- 1
- Unresolved
- 0
- Archived by EPA
- 2
- Any acute record
- No
- Monitoring issues, last 10 years
- 15
Key facts
- Grand Lake PWA draws water from 6 wells.
- Highest measured level in the last 10 years: Combined Radium (-226 and -228), 7 pCi/L, federal limit 5 pCi/L (1.4 times the limit), 2025.
- Most recent formal enforcement: compliance order (no penalty) by Oklahoma, November 2025.
- Record on file since 1993, with 29 health-based violations before October 19, 2016.
- Lead pipe inventory: 0 lead and 140 unknown out of 1,327 service lines.
Check whether Grand Lake PWA serves your address
Health-based violations
Since October 2016Violation data reflects EPA records through March 2026. For the most current status, visit the EPA ECHO database.
| Contaminant | Rule family | Start date | Status | Acute |
|---|---|---|---|---|
|
Combined Radium (-226 and -228)
Contaminant limit exceeded
Measured 7 pCi/L, federal limit 5 pCi/L (1.4 times the limit)
|
340 | Jul 1, 2025 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
No |
|
Combined Radium (-226 and -228)
Contaminant limit exceeded
Measured 6 pCi/L, federal limit 5 pCi/L (1.2 times the limit)
|
340 | Jan 1, 2024 | Resolved | No |
|
Combined Radium (-226 and -228)
Contaminant limit exceeded
Measured 6 pCi/L, federal limit 5 pCi/L (1.2 times the limit)
|
340 | Oct 1, 2023 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
No |
Monitoring and reporting issues
Since October 2016Missed tests or reports, not contaminants found above a limit.
| Issue | Start date | Status |
|---|---|---|
|
Lead and Copper Rule
Monitoring and reporting
|
Oct 1, 2024 | Resolved |
|
Consumer Confidence Rule
OTHER
|
Oct 2, 2023 | Resolved |
|
Gross Beta Particle Activity
Monitoring and reporting
|
Apr 1, 2022 | Resolved |
|
Combined Radium (-226 and -228)
Monitoring and reporting
|
Apr 1, 2022 | Resolved |
|
Combined Uranium
Monitoring and reporting
|
Apr 1, 2022 | Resolved |
|
Gross Alpha, Excl. Radon and U
Monitoring and reporting
|
Apr 1, 2022 | Resolved |
|
Gross Beta Particle Activity
Monitoring and reporting
|
Jan 1, 2022 | Resolved |
|
Combined Radium (-226 and -228)
Monitoring and reporting
|
Jan 1, 2022 | Resolved |
|
Combined Uranium
Monitoring and reporting
|
Jan 1, 2022 | Resolved |
|
Gross Alpha, Excl. Radon and U
Monitoring and reporting
|
Jan 1, 2022 | Resolved |
|
E. coli
Monitoring and reporting
|
Oct 20, 2020 | Resolved |
|
Revised Total Coliform Rule
Monitoring violation
|
Oct 1, 2018 | Resolved |
|
Chlorine
Monitoring and reporting
|
Oct 1, 2018 | Resolved |
|
Consumer Confidence Rule
OTHER
|
Jul 1, 2017 | Resolved |
|
Consumer Confidence Rule
OTHER
|
Jul 1, 2016 | Resolved |
Full record since 1993
EPA's records for Grand Lake PWA go back to 1993. Before October 19, 2016 they list 29 health-based violations (28 resolved, 1 archived by EPA without a recorded fix) and 52 monitoring or reporting violations.
| Violations that began in | Health-based | Monitoring and reporting |
|---|---|---|
| 1990s | 1 | 6 |
| 2000s | 13 | 40 |
| 2010 to October 18, 2016 | 15 | 6 |
| October 19, 2016 to 2019 | 0 | 3 |
| 2020s | 3 | 11 |
Most recent health-based violation before October 19, 2016: CARBON, TOTAL, began January 2014, Resolved.
Show all 29 health-based violations before October 19, 2016
| Contaminant | Start date | Status |
|---|---|---|
|
CARBON, TOTAL
Treatment technique failure
|
Jan 1, 2014 | Resolved |
|
CARBON, TOTAL
Treatment technique failure
|
Oct 1, 2013 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.084 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
Jul 1, 2013 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.102 mg/L, federal limit 0.06 mg/L (1.7 times the limit)
|
Jul 1, 2013 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.089 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
Apr 1, 2013 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.087 mg/L, federal limit 0.06 mg/L (1.5 times the limit)
|
Apr 1, 2013 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.075 mg/L, federal limit 0.06 mg/L (1.3 times the limit)
|
Jan 1, 2013 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.085 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
Jan 1, 2013 | Resolved |
|
CARBON, TOTAL
Treatment technique failure
|
Oct 1, 2012 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.075 mg/L, federal limit 0.06 mg/L (1.3 times the limit)
|
Oct 1, 2012 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.084 mg/L, federal limit 0.08 mg/L (1.1 times the limit)
|
Oct 1, 2012 | Resolved |
|
CARBON, TOTAL
Treatment technique failure
|
Jul 1, 2012 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.082 mg/L, federal limit 0.08 mg/L (at or just above the limit)
|
Jul 1, 2012 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.073 mg/L, federal limit 0.06 mg/L (1.2 times the limit)
|
Jul 1, 2012 | Resolved |
|
CARBON, TOTAL
Treatment technique failure
|
Apr 1, 2012 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.077 mg/L, federal limit 0.06 mg/L (1.3 times the limit)
|
Jan 1, 2009 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
Measured 0.069 mg/L, federal limit 0.06 mg/L (1.2 times the limit)
|
Oct 1, 2008 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.092 mg/L, federal limit 0.08 mg/L (1.2 times the limit)
|
Jan 1, 2006 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
|
Oct 1, 2005 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
|
Oct 1, 2005 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
|
Jul 1, 2005 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
|
Jul 1, 2005 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
|
Apr 1, 2005 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
|
Apr 1, 2005 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
|
Jan 1, 2005 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
|
Oct 1, 2004 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
|
Jul 1, 2004 | Resolved |
|
Haloacetic Acids (HAA5)
Contaminant limit exceeded
|
Apr 1, 2004 | Resolved |
|
Surface Water Treatment Rule
Treatment technique failure
|
Dec 1, 1993 | Archived |
Enforcement actions
Oklahoma regulators took 26 formal enforcement actions against Grand Lake PWA between 2002 and 2025. The most recent was a compliance order (no penalty) in November 2025.
| Date | By | Action | Violations covered |
|---|---|---|---|
| Nov 18, 2025 | Oklahoma | Compliance order (no penalty) | 1 violation (1 health-based): Combined Radium (-226 and -228) |
| Jun 19, 2024 | Oklahoma | Compliance order (no penalty) | 1 violation (1 health-based): Combined Radium (-226 and -228) |
| Jan 4, 2024 | Oklahoma | Compliance order (no penalty) | 1 violation (1 health-based): Combined Radium (-226 and -228) |
| Jun 20, 2014 | Oklahoma | Compliance order with a penalty | 1 violation (1 health-based): CARBON, TOTAL |
| Mar 14, 2014 | Oklahoma | Compliance order with a penalty | 3 violations (3 health-based): CARBON, TOTAL, Total Trihalomethanes (TTHMs), Haloacetic Acids (HAA5) |
| Jul 17, 2013 | Oklahoma | Compliance order with a penalty | 2 violations (2 health-based): Total Trihalomethanes (TTHMs), Haloacetic Acids (HAA5) |
| May 28, 2013 | Oklahoma | Compliance order with a penalty | 2 violations (2 health-based): Total Trihalomethanes (TTHMs), Haloacetic Acids (HAA5) |
| Feb 4, 2013 | Oklahoma | Compliance order with a penalty | 3 violations (3 health-based): CARBON, TOTAL, Total Trihalomethanes (TTHMs), Haloacetic Acids (HAA5) |
| Nov 20, 2012 | Oklahoma | Compliance order with a penalty | 3 violations (3 health-based): Haloacetic Acids (HAA5), Total Trihalomethanes (TTHMs), CARBON, TOTAL |
| Aug 21, 2012 | Oklahoma | Compliance order with a penalty | 1 violation (1 health-based): CARBON, TOTAL |
| Apr 22, 2011 | Oklahoma | Compliance order with a penalty | 4 violations: Consumer Confidence Rule |
| May 29, 2009 | Oklahoma | Compliance order with a penalty | 1 violation (1 health-based): Haloacetic Acids (HAA5) |
| Mar 30, 2009 | Oklahoma | Compliance order with a penalty | 1 violation: CARBON, TOTAL |
| Feb 10, 2009 | Oklahoma | Compliance order with a penalty | 1 violation (1 health-based): Haloacetic Acids (HAA5) |
| Jan 23, 2008 | Oklahoma | Compliance order with a penalty | 1 violation: Nitrate-Nitrite |
| Aug 10, 2006 | Oklahoma | Compliance order with a penalty | 1 violation (1 health-based): Total Trihalomethanes (TTHMs) |
| Apr 11, 2006 | Oklahoma | Compliance order with a penalty | 3 violations (2 health-based): Total Trihalomethanes (TTHMs), CARBON, TOTAL, Haloacetic Acids (HAA5) |
| Jan 26, 2006 | Oklahoma | Compliance order with a penalty | 4 violations (4 health-based): Haloacetic Acids (HAA5), Total Trihalomethanes (TTHMs) |
| Jan 12, 2006 | Oklahoma | Compliance order with a penalty | 1 violation: Chlorine |
| Nov 16, 2005 | Oklahoma | Compliance order with a penalty | 11 violations: Surface Water Treatment Rule, Interim Enhanced Surface Water Treatment Rule |
| Sep 20, 2005 | Oklahoma | Compliance order with a penalty | 5 violations (1 health-based): CARBON, TOTAL, Haloacetic Acids (HAA5) |
| Apr 7, 2005 | Oklahoma | Compliance order with a penalty | 1 violation (1 health-based): Haloacetic Acids (HAA5) |
| Feb 3, 2005 | Oklahoma | Compliance order (no penalty) | 8 violations (8 health-based): Haloacetic Acids (HAA5), Total Trihalomethanes (TTHMs) |
| Jan 11, 2005 | Oklahoma | Compliance order with a penalty | 1 violation (1 health-based): Haloacetic Acids (HAA5) |
| Oct 8, 2004 | Oklahoma | Compliance order with a penalty | 1 violation (1 health-based): Haloacetic Acids (HAA5) |
| Dec 23, 2002 | Oklahoma | Compliance order with a penalty | 2 violations: Surface Water Treatment Rule |
What the violations mean
Combined Radium (-226 and -228)
3 incidentsTest results for Combined Radium (-226 and -228) were above the federal limit (a maximum contaminant level violation).
The utility had to notify customers about each of these violations.
Where the water comes from
Grand Lake PWA draws water from 6 wells.
Annual water quality report
Grand Lake PWA must give its customers an annual water quality report (Consumer Confidence Report) by July 1, with the levels its tests found in the previous year.
Where the state allows it, systems serving fewer than 10,000 people may publish the report in a local newspaper or news site instead of mailing it, and must provide a copy on request.
Find a posted report with EPA's Consumer Confidence Report search
Testing your own water
To test the water at your tap, or a private well this record does not cover, use a laboratory certified for drinking water by Oklahoma.
Certified drinking water labs by state EPA guidance for private wells