Duncan, OK Tap Water Quality 2026

Water quality report for Duncan, OK — PFAS, lead and copper results, violation history and state inspection findings from EPA SDWIS.

A look at Duncan's drinking water using EPA enforcement records: violations, lead and copper results, PFAS sampling and state inspection findings.

Main Utility: Duncan Public Utilities Authority PWSID: OK1010809 Updated: 2026 Q2

✅

No federal limits exceeded on record

Lead was not detected and no violations are open. No PFAS was detected.

Duncan earns a B for water quality

Graded on violations, lead, and PFAS, with state inspection findings.

Lead: not detected

PFAS tested, none detected

61 violations since 2015, 50 health-based

No violations currently open

Duncan's lead level vs. all Oklahoma community water systems

0 ppb5 ppb10 ppb15 ppb

Lead level: Not detected — 0% of the federal action level

✓ Lower lead than % of Oklahoma utilities

Population Served

9457

~10938 connections

Water Source

Surface water

Drawn from surface water — SDWIS source code SW

Active Violations

61 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)

90th percentile of tap samples collected across the distribution system

0% of EPA action level

Not detected

Action level: 15 ppb

Lead was not detected at the 90th percentile — the result fell below the laboratory detection limit. That is not the same as an absence of lead in every tap, and older homes with lead service lines can still show higher readings.

Contaminant Violations (2015–Present)

Contaminant	Type	Measured	Limit	Period	Status
Revised Total Coliform Rule	MONITORING FAILURE	—	—	2025	Archived
Chloramine	MONITORING AND REPORTING	—	4.0 mg/L	2025	Resolved
Chloramine	MONITORING AND REPORTING	—	4.0 mg/L	2024	Resolved
Revised Total Coliform Rule	MONITORING FAILURE	—	—	2024	Resolved
CARBON, TOTAL	TREATMENT TECHNIQUE	0.9 RATIO	TT	2024	Archived
CARBON, TOTAL	MONITORING AND REPORTING	—	TT	2024	Resolved
CARBON, TOTAL	MONITORING AND REPORTING	—	TT	2024	Resolved
CARBON, TOTAL	TREATMENT TECHNIQUE	0.88 RATIO	TT	2024	Archived
CARBON, TOTAL	TREATMENT TECHNIQUE	0.98 RATIO	TT	2024	Archived
CARBON, TOTAL	TREATMENT TECHNIQUE	0.99 RATIO	TT	2024	Archived
TTHM	MCL EXCEEDANCE	0.081 MG/L	0.080 mg/L	2023	Archived
TTHM	MCL EXCEEDANCE	0.081 MG/L	0.080 mg/L	2020	Archived
TTHM	MCL EXCEEDANCE	0.085 MG/L	0.080 mg/L	2020	Archived
TTHM	MCL EXCEEDANCE	0.083 MG/L	0.080 mg/L	2020	Archived
TTHM	MCL EXCEEDANCE	0.082 MG/L	0.080 mg/L	2020	Archived
CARBON, TOTAL	TREATMENT TECHNIQUE	—	TT	2020	Resolved
TTHM	MCL EXCEEDANCE	0.084 MG/L	0.080 mg/L	2019	Archived
TTHM	MCL EXCEEDANCE	0.081 MG/L	0.080 mg/L	2019	Resolved
TTHM	MCL EXCEEDANCE	0.084 MG/L	0.080 mg/L	2019	Archived
TTHM	MCL EXCEEDANCE	0.085 MG/L	0.080 mg/L	2019	Archived
TTHM	MCL EXCEEDANCE	0.087 MG/L	0.080 mg/L	2019	Resolved
TTHM	MCL EXCEEDANCE	0.09 MG/L	0.080 mg/L	2019	Resolved
TTHM	MCL EXCEEDANCE	0.089 MG/L	0.080 mg/L	2019	Resolved
TTHM	MCL EXCEEDANCE	0.091 MG/L	0.080 mg/L	2019	Resolved
TTHM	MCL EXCEEDANCE	0.1 MG/L	0.080 mg/L	2019	Resolved
TTHM	MCL EXCEEDANCE	0.094 MG/L	0.080 mg/L	2019	Archived
TTHM	MCL EXCEEDANCE	0.098 MG/L	0.080 mg/L	2019	Archived
TTHM	MCL EXCEEDANCE	0.095 MG/L	0.080 mg/L	2019	Archived
TTHM	MCL EXCEEDANCE	0.106 MG/L	0.080 mg/L	2019	Resolved
TTHM	MCL EXCEEDANCE	0.1 MG/L	0.080 mg/L	2019	Archived
TTHM	MCL EXCEEDANCE	0.105 MG/L	0.080 mg/L	2019	Archived
TTHM	MCL EXCEEDANCE	0.102 MG/L	0.080 mg/L	2019	Archived
TTHM	MCL EXCEEDANCE	0.106 MG/L	0.080 mg/L	2018	Archived
TTHM	MCL EXCEEDANCE	0.106 MG/L	0.080 mg/L	2018	Archived
TTHM	MCL EXCEEDANCE	0.134 MG/L	0.080 mg/L	2018	Resolved
TTHM	MCL EXCEEDANCE	0.134 MG/L	0.080 mg/L	2018	Resolved
Chloramine	MONITORING AND REPORTING	—	4.0 mg/L	2017	Resolved
TTHM	MCL EXCEEDANCE	0.17 MG/L	0.080 mg/L	2017	Resolved
Total Haloacetic Acids (HAA5)	MCL EXCEEDANCE	0.069 MG/L	0.060 mg/L	2017	Resolved
TTHM	MCL EXCEEDANCE	0.207 MG/L	0.080 mg/L	2017	Resolved
TTHM	MONITORING AND REPORTING	—	0.080 mg/L	2017	Resolved
Total Haloacetic Acids (HAA5)	MONITORING AND REPORTING	—	0.060 mg/L	2017	Resolved
Total Haloacetic Acids (HAA5)	MCL EXCEEDANCE	0.065 MG/L	0.060 mg/L	2017	Archived
TTHM	MCL EXCEEDANCE	0.147 MG/L	0.080 mg/L	2017	Archived
Interim Enhanced Surface Water Treatment Rule	TREATMENT TECHNIQUE	—	—	2016	Resolved
TTHM	MONITORING AND REPORTING	—	0.080 mg/L	2016–2017	Resolved
Total Haloacetic Acids (HAA5)	MONITORING AND REPORTING	—	0.060 mg/L	2016–2017	Resolved
Total Haloacetic Acids (HAA5)	MCL EXCEEDANCE	0.075 MG/L	0.060 mg/L	2016	Archived
TTHM	MCL EXCEEDANCE	0.16 MG/L	0.080 mg/L	2016	Archived
Total Haloacetic Acids (HAA5)	MCL EXCEEDANCE	0.064 MG/L	0.060 mg/L	2016	Archived
TTHM	MCL EXCEEDANCE	0.149 MG/L	0.080 mg/L	2016	Resolved
TTHM	MCL EXCEEDANCE	0.16 MG/L	0.080 mg/L	2016	Resolved
Total Haloacetic Acids (HAA5)	MCL EXCEEDANCE	0.062 MG/L	0.060 mg/L	2016	Resolved
TTHM	MCL EXCEEDANCE	0.154 MG/L	0.080 mg/L	2016	Archived
Total Haloacetic Acids (HAA5)	MCL EXCEEDANCE	0.061 MG/L	0.060 mg/L	2016	Resolved
TTHM	MCL EXCEEDANCE	0.148 MG/L	0.080 mg/L	2015	Archived
TTHM	MCL EXCEEDANCE	0.132 MG/L	0.080 mg/L	2015	Archived
TTHM	MCL EXCEEDANCE	0.147 MG/L	0.080 mg/L	2015	Archived
CARBON, TOTAL	TREATMENT TECHNIQUE	—	TT	2015	Archived
TTHM	MCL EXCEEDANCE	0.121 MG/L	0.080 mg/L	2015	Resolved
CARBON, TOTAL	TREATMENT TECHNIQUE	—	TT	2015	Archived

Understanding violation types MCL violations mean a contaminant exceeded the federal maximum limit — the most serious type.
TT (Treatment Technique) violations mean required treatment procedures weren't followed, but don't necessarily mean contamination occurred.

Violation History

61 violations are on record since 2015, of which 50 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility Duncan Public Utilities Authority

PWSID OK1010809

Water source Surface water — Drawn from surface water — SDWIS source code SW

Population served 9,457

Service connections 10,938

Systems serving this area 4

Regulator State primacy agency

Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Duncan tap water safe to drink? ▼

No federal limit is exceeded on record. No violations are currently open.

Does Duncan water have PFAS? ▼

It was tested for the six regulated PFAS compounds and none were detected.

Who supplies water to Duncan? ▼

Duncan Public Utilities Authority (PWSID OK1010809), one of 4 systems serving this area. Surface water. Drawn from surface water — SDWIS source code SW

When was this system last inspected? ▼

It was last inspected on 2025-07-29. No significant deficiencies were recorded.

What Should Duncan Residents Do?

Read your annual water report

Your supplier publishes a Consumer Confidence Report each July covering the prior year.

Check for a lead service line

Lead reaches tap water mainly through service lines and household plumbing. Suppliers now publish an inventory identifying lead lines.

Flush before drinking

If water has sat in pipes more than six hours, run the cold tap for two minutes before drinking or cooking.

Nearby Cities in Oklahoma

Marlow, Ok Tap Water Quality 2026 Stephens Central High, Ok Tap Water Quality 2026 Stephens Bray, Ok Tap Water Quality 2026 Stephens Sunray, Ok Tap Water Quality 2026 Stephens Comanche, Ok Tap Water Quality 2026 Stephens Empire City, Ok Tap Water Quality 2026 Stephens