OK / Wister
OK · Tap water records
Wister tap water, in plain English
Here is what the EPA's own data shows about tap water in Wister. According to EPA SDWIS data retrieved June 2026, Wister is served by 4 active community water systems, together reported to serve about 5,057 people.
As of June 2026, EPA records show 456 violations across the community water system(s) serving Wister, going back to the earliest EPA record. 150 of these are classified by the EPA as health-based (a contaminant recorded above the limit the EPA tracks); the rest are monitoring or reporting violations. Each is listed by system below, with its status.
What the EPA has on record, by system
Leflore Co. Rwd #18
3,870 served · surface water · PWSID OK3004009 - Health-based Total Haloacetic Acids (HAA5): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 11 times between July 2019 and October 2025. The EPA record lists a level of 0.064 MG/L; the limit (MCL) is 0.06 MG/L. EPA records do not show all of these as returned to compliance.
- Health-based LEAD AND COPPER RULE REVISIONS: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in October 2024. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
- Health-based TTHM: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 36 times between April 2018 and April 2023. The EPA record lists a level of 0.082 MG/L; the limit (MCL) is 0.08 MG/L. EPA records do not show all of these as returned to compliance.
- Monitoring Chlorine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between October 2015 and October 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2025. EPA records do not show all of these as returned to compliance.
- Monitoring LEAD AND COPPER RULE REVISIONS: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2024. EPA records do not show all of these as returned to compliance.
- Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in April 2018. All have since returned to compliance, per EPA records.
- Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in April 2018. All have since returned to compliance, per EPA records.
- Monitoring Coliform (TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 6 times between April 1991 and September 1992. All have since returned to compliance, per EPA records.
- Monitoring Coliform (Pre-TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 12 times between November 1980 and January 1984. All have since returned to compliance, per EPA records.
Wister
1,002 served · surface water · PWSID OK3004014 - Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in September 2025. All have since returned to compliance, per EPA records.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 6 times between July 2023 and July 2024. All have since returned to compliance, per EPA records.
- Monitoring Coliform (TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 5 times between December 1991 and March 1999. All have since returned to compliance, per EPA records.
- Monitoring Coliform (Pre-TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 8 times between October 1979 and August 1984. All have since returned to compliance, per EPA records.
Latimer Co. Rwd #3
175 served · surface water · PWSID OK3003908 - Health-based TTHM: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 76 times between January 2016 and October 2025. The EPA record lists a level of 0.192 MG/L; the limit (MCL) is 0.08 MG/L. EPA records do not show all of these as returned to compliance.
- Health-based LEAD AND COPPER RULE REVISIONS: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in October 2024. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
- Health-based Total Haloacetic Acids (HAA5): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in January 2016. The EPA record lists a level of 0.063 MG/L; the limit (MCL) is 0.06 MG/L. EPA records do not show all of these as returned to compliance.
- Health-based Coliform (TCR): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 3 times between June 1998 and December 1998. The EPA record lists a level of 0 ; the limit (MCL) is 0 . All have since returned to compliance, per EPA records.
- Monitoring Chlorine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 38 times between January 2019 and November 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 27 times between February 2019 and November 2025. EPA records do not show all of these as returned to compliance.
- Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 58 times between June 2015 and October 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 27 times between September 2015 and October 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 9 times between June 1993 and July 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 13 times between July 2016 and July 2025. EPA records do not show all of these as returned to compliance.
- Monitoring Public Notice: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 42 times between January 2017 and November 2024. EPA records do not show all of these as returned to compliance.
- Monitoring LEAD AND COPPER RULE REVISIONS: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2024. EPA records do not show all of these as returned to compliance.
- Monitoring Coliform (TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between November 1998 and January 1999. All have since returned to compliance, per EPA records.
Poteau Valley Improvement Authority
10 served · surface water · PWSID OK1020104 - Health-based Total Haloacetic Acids (HAA5): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 5 times between July 2019 and July 2025. The EPA record lists a level of 0.064 MG/L; the limit (MCL) is 0.06 MG/L. EPA records do not show all of these as returned to compliance.
- Health-based Interim Enhanced Surface Water Treatment Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times in February 2025. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
- Health-based LEAD AND COPPER RULE REVISIONS: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in October 2024. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Health-based TTHM: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 9 times between December 1984 and January 2023. The EPA record lists a level of 0.086 MG/L; the limit (MCL) is 0.08 MG/L. EPA records do not show all of these as returned to compliance.
- Health-based Surface Water Treatment Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in August 2018. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Health-based Coliform (TCR): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in July 1993. The EPA record lists a level of 0 ; the limit (MCL) is 0 . All have since returned to compliance, per EPA records.
- Health-based Coliform (Pre-TCR): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times between November 1988 and May 1990. The EPA record lists a level of 80 ; the limit (MCL) is 0 . All have since returned to compliance, per EPA records.
- Monitoring LEAD AND COPPER RULE REVISIONS: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2024. All have since returned to compliance, per EPA records.
- Monitoring Glyphosate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2024. EPA records do not show all of these as returned to compliance.
- Monitoring Atrazine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2024. EPA records do not show all of these as returned to compliance.
- Monitoring 2,4-D: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2024. EPA records do not show all of these as returned to compliance.
- Monitoring Chlorite: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 11 times between August 2022 and June 2023. EPA records do not show all of these as returned to compliance.
- Monitoring Surface Water Treatment Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 2017. All have since returned to compliance, per EPA records.
- Monitoring Coliform (TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in May 1991. All have since returned to compliance, per EPA records.
- Monitoring Turbidity: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 10 times between October 1983 and September 1984. All have since returned to compliance, per EPA records.
- Monitoring Coliform (Pre-TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 5 times between March 1983 and July 1984. All have since returned to compliance, per EPA records.
What this means
A health-based violation means a contaminant was recorded above the limit the EPA tracks for it. A monitoring or reporting violation means a required test or report was late or missed — not that a contaminant was measured above a limit. “Returned to compliance” means the EPA recorded the issue as resolved.
This page summarizes the EPA's own records and does not assess whether your water is safe to drink. For the most current details, you can verify every record directly with the EPA, and contact your water system with questions.
Source: U.S. EPA Envirofacts SDWIS, retrieved June 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.