F0/100
Duncan Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 23,000 residents · Oklahoma
What's In Duncan's Tap Water?
69
Contaminants Tested
0
Exceed EPA Limits
0
Above EPA Goals
EPA Violation History
9
Violations (last 5yr)
5
Unresolved
5
Health-Related
TIER 3Resolved
Monitoring Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: November 1, 2024 – November 30, 2024Rule: Total Coliform 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: November 1, 2024 – November 30, 2024Rule: Stage 1 DBPREnforcement: Resolving — corrective action underway
TIER 2Unresolved
Treatment Technique Violation
When: October 1, 2024 – December 31, 2024Rule: Stage 1 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
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: August 1, 2024 – August 31, 2024Rule: Stage 1 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: August 1, 2024 – August 31, 2024Rule: Stage 1 DBPREnforcement: Resolving — corrective action underway
TIER 2Unresolved
Treatment Technique Violation
When: July 1, 2024 – September 30, 2024Rule: Stage 1 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved
Treatment Technique Violation
When: April 1, 2024 – June 30, 2024Rule: Stage 1 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Unresolved
Treatment Technique Violation
When: January 1, 2024 – March 31, 2024Rule: Stage 1 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
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
DUNCAN PUBLIC UTILITIES AUTHORITY
Population Served
23,000
Water Source
Surface Water
System ID
OK1010809
Frequently Asked Questions About Duncan Water
Is Duncan tap water safe to drink?
Duncan, Oklahoma tap water receives a grade of F (0/100), which is considered failing. 0 contaminant(s) exceed EPA maximum contaminant levels and 165 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Duncan's water?
69 contaminants were tested in Duncan's water supply. No contaminants exceed EPA legal limits (MCLs) or health goals (MCLGs), which is a positive indicator of water quality.
Does Duncan have any water quality violations?
Yes, Duncan has 165 EPA violation(s) on record, with the most recent in 2024. Violation types include MON, MR, TT. 150 of these are health-based violations, which are the most serious category.
Do I need a water filter in Duncan?
Duncan 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 Duncan's tap water come from?
Duncan's drinking water is sourced from surface water and supplied by DUNCAN PUBLIC UTILITIES AUTHORITY. The system serves approximately 23,000 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Duncan'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. Duncan'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 Duncan's water compare to other cities in Oklahoma?
Duncan's water quality score of 0/100 earns a grade of F, which is considered failing. 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 Duncan's water quality?
If you have concerns about Duncan'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 (DUNCAN PUBLIC UTILITIES AUTHORITY) 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.