D36/100
Wister Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 4,872 residents · Oklahoma
What's In Wister's Tap Water?
51
Contaminants Tested
0
Exceed EPA Limits
0
Above EPA Goals
EPA Violation History
9
Violations (last 5yr)
9
Unresolved
8
Health-Related
TIER 2Unresolved
Exceeded the Maximum Contaminant Level (running average)
When: July 1, 2025 – September 30, 2025Rule: Stage 2 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved
Exceeded the Maximum Contaminant Level (running average)
When: July 1, 2025 – September 30, 2025Rule: Stage 2 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
TIER 3Unresolved
Reporting violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: October 17, 2024Rule: Ground Water RuleEnforcement: Informal — resolved cooperativelyVerify on EPA.gov
TIER 2Unresolved
Treatment technique violation
When: October 17, 2024Rule: Ground Water RuleEnforcement: Informal — resolved cooperativelyVerify on EPA.gov
TIER 2Unresolved
Exceeded the Maximum Contaminant Level (running average)
When: April 1, 2023 – June 30, 2023Rule: Stage 2 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved
Exceeded the Maximum Contaminant Level (running average)
When: January 1, 2023 – March 31, 2023Rule: Stage 2 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved
Exceeded the Maximum Contaminant Level (running average)
When: October 1, 2022 – December 31, 2022Rule: Stage 2 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved
Exceeded the Maximum Contaminant Level (running average)
When: July 1, 2022 – September 30, 2022Rule: Stage 2 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved
Exceeded the Maximum Contaminant Level (running average)
When: April 1, 2022 – June 30, 2022Rule: Stage 2 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
LEFLORE CO. RWD #18
Population Served
3,870
Water Source
Purchased Surface Water
System ID
OK3004009
WISTER
Population Served
1,002
Water Source
Purchased Surface Water
System ID
OK3004014
Frequently Asked Questions About Wister Water
Is Wister tap water safe to drink?
Wister, Oklahoma tap water receives a grade of D (36/100), which is considered poor. 0 contaminant(s) exceed EPA maximum contaminant levels and 59 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Wister's water?
51 contaminants were tested in Wister's water supply. No contaminants exceed EPA legal limits (MCLs) or health goals (MCLGs), which is a positive indicator of water quality.
Does Wister have any water quality violations?
Yes, Wister has 59 EPA violation(s) on record, with the most recent in 2025. Violation types include MR, MCL, RPT. 17 of these are health-based violations, which are the most serious category.
Do I need a water filter in Wister?
Wister water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. All contaminants are within health goals.
Where does Wister's tap water come from?
Wister's drinking water is sourced from purchased surface water and supplied by LEFLORE CO. RWD #18 and 1 other water system(s). The system serves approximately 4,872 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Wister's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Wister's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does Wister's water compare to other cities in Oklahoma?
Wister's water quality score of 36/100 earns a grade of D, which is considered poor. This is a concerning score that suggests significant water quality issues. Visit our Oklahoma state page to see how all cities in the state compare.
What should I do if I'm concerned about Wister's water quality?
If you have concerns about Wister's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (LEFLORE CO. RWD #18) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.