D26/100
Tonkawa Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 3,299 residents · Oklahoma
What's In Tonkawa's Tap Water?
2
Contaminants Tested
1
Exceed EPA Limits
1
Above EPA Goals
2 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Copper (90th percentile) | 3.30 mg/L | 1.30 mg/L | Over Limit |
Lead (90th percentile) | 0.006 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
5
Violations (last 5yr)
1
Unresolved
1
Health-Related
TIER 3Unresolved
Failed to conduct Level 1 Assessment
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: August 14, 2025Rule: Consumer Confidence RuleEnforcement: Informal — resolved cooperativelyVerify on EPA.gov
TIER 3Resolved
Reporting violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: October 17, 2024 – July 15, 2025Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 2Resolved
Treatment technique violation
When: October 17, 2024 – July 15, 2025Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: October 1, 2022 – September 30, 2023Rule: Stage 2 DBPREnforcement: Resolving — corrective action underway
TIER 3Resolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: October 1, 2022 – September 30, 2023Rule: Stage 2 DBPREnforcement: Resolving — corrective action underway
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
TONKAWA
Population Served
3,299
Water Source
Groundwater
System ID
OK2003603
Frequently Asked Questions About Tonkawa Water
Is Tonkawa tap water safe to drink?
Tonkawa, Oklahoma tap water receives a grade of D (26/100), which is considered poor. 1 contaminant(s) exceed EPA maximum contaminant levels and 39 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Tonkawa's water?
Of the 2 contaminants tested in Tonkawa's water supply, the most notable include Copper (90th percentile), Lead (90th percentile). 1 contaminant(s) exceed EPA legal limits (MCLs). 2 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does Tonkawa have any water quality violations?
Yes, Tonkawa has 39 EPA violation(s) on record, with the most recent in 2025. Violation types include MR, RPT, TT. 6 of these are health-based violations, which are the most serious category.
Do I need a water filter in Tonkawa?
Based on EPA data, using a water filter in Tonkawa is recommended. 1 contaminant(s) exceed legal limits. An NSF-certified filter — such as a reverse osmosis or activated carbon system — can effectively reduce many common contaminants. Choose a filter certified to remove the specific contaminants found in your area.
Where does Tonkawa's tap water come from?
Tonkawa's drinking water is sourced from groundwater and supplied by TONKAWA. The system serves approximately 3,299 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is Tonkawa'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. Tonkawa'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 Tonkawa's water compare to other cities in Oklahoma?
Tonkawa's water quality score of 26/100 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 Tonkawa's water quality?
If you have concerns about Tonkawa'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 (TONKAWA) 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.