City water report · 2026

Is Duncan Tap Water Safe to Drink?

Short answer: In the 2022–2024 records we hold for Duncan, no listed result is above a legal limit, but 9 health-based violations are on record (EPA SDWIS). Also worth knowing: lithium sits above a screening level. 5 substances were detected and 26 were tested and not detected. The water is from Duncan Public Utilities Authority, serving 23,000 residents.

  • Year 2026
  • Utility Duncan Public Utilities Authority
  • Coverage 31 records
  • Updated 2026-10-15
Water utility

Where Duncan’s water comes from

Utility
Duncan Public Utilities Authority
Water system
DUNCAN PUBLIC UTILITIES AUTHORITY · OK1010809
Source water
Surface water
Disinfectant
not on record
Population served
23,000
Reporting period
Sampled 2022–2024
Monitoring coverage
31 records · 3 of 4 groups measured
Service lines
10,938 unknown material (EPA inventory, 2026Q2)
Likely match, check your bill

Your water bill or annual water quality report names your actual supplier.

Why this matters
  1. 1
    Source

    Surface water

  2. 2
    Treatment

    The treatment details are not on record.

  3. 3
    Distribution

    Mains, then your building’s service line.

  4. 4
    Your tap

    Plumbing inside the building is outside this record.

At a glance

Duncan water in four numbers

Purity ScoreDUNCAN PUBLIC UTILITIES AUTHORITY · PWSID OK1010809
5Detected1 above a reference
1Above a referenceof 31 records
9Health-based violationslast 10 years · EPA SDWIS

No measured result is above a legal limit; lithium sits above a screening level.

What we found

5 detected results, by distance from their limit

LithiumAbove screening · Screening level10 µg/L EPA health reference level (screening, not a legal limit)14.2µg/L
① · Measured

14.2 µg/L, sampled 2023-10-03 to 2024-07-10. EPA UCMR 5.

② · Compared

10 µg/L EPA health reference level (screening, not a legal limit).

③ · Meaning

Detected at up to 14.2 µg/L (above the 10 µg/L EPA health reference level; a screening level, not a legal limit).

④ · Where it matters

Where it enters is not in this record.

⑤ · What to do

Test your own tap first. To reduce it: Depends on the contaminant (The certifier's listing for each named contaminant).

See the evidence record →
Perfluorohexanoic acid (PFHxA)Within reference · State limit400,000 ng/L Michigan EGLE state MCL (strictest US state)3.3ng/L
① · Measured

3.3 ng/L, sampled 2023-10-03 to 2024-07-10. EPA UCMR 5.

② · Compared

400,000 ng/L Michigan EGLE state MCL (strictest US state): a state limit.

③ · Meaning

Detected at up to 3.3 ng/L (below the 400,000 ng/L historical comparison reference).

④ · Where it matters

Comes with the source water; home plumbing does not add it.

⑤ · What to do

Test your own tap first. To reduce it: Reverse osmosis, or carbon certified for PFAS (NSF/ANSI 53 or 58, with PFHxA named on the listing).

See the evidence record →
Perfluorobutanoic acid (PFBA)Detected · no limit · No federal limitNo federal or state limit; shown for transparency7.5ng/L
① · Measured

7.5 ng/L, sampled 2023-10-03 to 2024-07-10. EPA UCMR 5.

② · Compared

No federal limit is on record for it.

③ · Meaning

Detected at up to 7.5 ng/L. No federal or state limit exists for this substance; shown for transparency, not graded.

④ · Where it matters

Comes with the source water; home plumbing does not add it.

⑤ · What to do

Test your own tap first. To reduce it: Reverse osmosis, or carbon certified for PFAS (NSF/ANSI 53 or 58, with PFBA named on the listing).

See the evidence record →
Perfluoroheptanoic acid (PFHpA)Detected · no limit · No federal limitNo federal or state limit; shown for transparency3.4ng/L
① · Measured

3.4 ng/L, sampled 2023-10-03 to 2024-07-10. EPA UCMR 5.

② · Compared

No federal limit is on record for it.

③ · Meaning

Detected at up to 3.4 ng/L. No federal or state limit exists for this substance; shown for transparency, not graded.

④ · Where it matters

Comes with the source water; home plumbing does not add it.

⑤ · What to do

Test your own tap first. To reduce it: Reverse osmosis, or carbon certified for PFAS (NSF/ANSI 53 or 58, with PFHpA named on the listing).

See the evidence record →
Perfluoropentanoic acid (PFPeA)Detected · no limit · No federal limitNo federal or state limit; shown for transparency3.8ng/L
① · Measured

3.8 ng/L, sampled 2023-10-03 to 2024-07-10. EPA UCMR 5.

② · Compared

No federal limit is on record for it.

③ · Meaning

Detected at up to 3.8 ng/L. No federal or state limit exists for this substance; shown for transparency, not graded.

④ · Where it matters

Comes with the source water; home plumbing does not add it.

⑤ · What to do

Test your own tap first. To reduce it: Reverse osmosis, or carbon certified for PFAS (NSF/ANSI 53 or 58, with PFPeA named on the listing).

See the evidence record →
26 others tested, none detectedshow
  • 11Cl-PF3OUdS
  • 8:2 FTS
  • 4:2 FTS
  • 6:2 FTS
  • ADONA
  • 9Cl-PF3ONS
  • HFPO-DA (GenX)
  • Lead (90th percentile)
  • NEtFOSAA
  • NMeFOSAA
  • NFDHA
  • PFEESA
  • PFMPA
  • PFMBA
  • PFBS
  • PFDA
  • PFDoA
  • PFHpS
  • PFHxS
  • PFNA
  • PFOS
  • PFOA
  • PFPeS
  • PFTA
  • PFTrDA
  • PFUnA

DUNCAN PUBLIC UTILITIES AUTHORITY (EPA PWSID OK1010809) delivers surface water to 23,000 residents. This report reflects 29 individual PFAS result(s) from the source UCMR5 observations and the latest Lead & Copper Rule 90th-percentile result. Water hardness and disinfectant type are pending the utility's own annual report.

Track record

9health-based violations in the last 10 years

From EPA SDWIS. Counted once per contaminant per year, as in the Track record score. All 36 EPA filings are listed below.

Not in this recordDisinfection by-products weren't monitored in this dataset

No result is not a pass. Your utility's annual water quality report may list them, and a certified lab test covers your own tap.

Health-based violations, last 10 years

Every filing is listed; the Track record score counts at most one per contaminant per year.

Filings 2015–2024
  • Carbon, total
  • TTHM
  • Total Haloacetic Acids (HAA5)
  • Interim Enhanced Surface Water Treatment Rule

Resolved

  1. Carbon, totalTT

    to Resolved

    EPA status: ArchivedSDWIS ID 8006963

  2. Carbon, totalTT

    to Resolved

    EPA status: ArchivedSDWIS ID 8006964

  3. Carbon, totalTT

    to Resolved

    EPA status: ArchivedSDWIS ID 8006949

  4. Carbon, totalTT

    to Resolved

    EPA status: ArchivedSDWIS ID 8006945

  5. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006932

  6. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006917

  7. Carbon, totalTT

    to Resolved

    EPA status: ResolvedSDWIS ID 8006915

  8. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006914

  9. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006913

  10. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006912

Show 26 more
  1. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006909

  2. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006908

  3. TTHMMCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006907

  4. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006906

  5. TTHMMCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006904

  6. TTHMMCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006903

  7. TTHMMCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006902

  8. TTHMMCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006901

  9. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006900

  10. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006899

  11. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006898

  12. TTHMMCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006897

  13. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006896

  14. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006895

  15. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006894

  16. TTHMMCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006893

  17. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006888

  18. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006884

  19. TTHMMCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006878

  20. TTHMMCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006873

  21. TTHMMCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006869

  22. TTHMMCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006862

  23. Total Haloacetic Acids (HAA5)MCL

    to Resolved

    EPA status: ResolvedSDWIS ID 8006861

  24. TTHMMCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006844

  25. Total Haloacetic Acids (HAA5)MCL

    to Resolved

    EPA status: ArchivedSDWIS ID 8006841

  26. Interim Enhanced Surface Water Treatment RuleTT

    to Resolved

    EPA status: ResolvedSDWIS ID 8006827

Your household

Your tap can differ from the city record

The record describes water leaving treatment and samples across the system. Pipes, solder and fixtures inside a building can add lead the record can’t see, especially in older buildings with lead service lines.

Test your water
  1. City
    Treated water

    Measured in this report

  2. Mains
    Distribution network

    Sampled across the system

  3. Building
    Service line and plumbing

    Not in this record

  4. Tap
    Your glass

    Only a tap test measures it

Test first, then treat

Water testing in Duncan, OK

  1. 01Test

    Know what comes from your tap, starting with a first-draw lead sample.

  2. 02Match

    Compare each result with its named reference in our test reader.

  3. 03Treat

    Choose a technology certified for what your test found.

Commercial

Test kits

Affiliate links

Screening tells you if something is worth a closer look; a lab result is the number you can act on.

As an Amazon Associate, PurityMap earns from qualifying purchases. Affiliate disclosure.

  • Lab-certified results

    ETR Labs Basic Water Quality Test Kit

    ETR Laboratories

    50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria

    What it can't tell you: It does not test PFAS, and not every result on the panel falls under the lab's accredited scope.

  • Screening: quick check, not lab-grade

    Watersafe Drinking Water Test Kit

    Silver Lake Research

    Lead, bacteria, nitrate, copper, iron, chlorine, hardness and pH

    • Turnaround: Minutes; the bacteria test can take up to 48 hours

    What it can't tell you: Each test gives a yes/no or a rough range, not a lab number, and it cannot detect PFAS or arsenic.

When your results arrive, read them here → · Compare every kit we list

Oklahoma Department of Environmental Quality certifies the labs that test drinking water in Oklahoma. Find a certified lab in Oklahoma ↗ · What lab tests cost →

Treatment matching

What can reduce what was found here

FindingReference typeTechnologyCertification to check
Lithium14.2 µg/LScreening levelDepends on the contaminantThe certifier's listing for each named contaminant
Perfluorohexanoic acid (PFHxA)3.3 ng/LState limitReverse osmosis, or carbon certified for PFASNSF/ANSI 53 or 58, with PFHxA named on the listing
Perfluorobutanoic acid (PFBA)7.5 ng/LNo federal limitReverse osmosis, or carbon certified for PFASNSF/ANSI 53 or 58, with PFBA named on the listing
Perfluoroheptanoic acid (PFHpA)3.4 ng/LNo federal limitReverse osmosis, or carbon certified for PFASNSF/ANSI 53 or 58, with PFHpA named on the listing
Perfluoropentanoic acid (PFPeA)3.8 ng/LNo federal limitReverse osmosis, or carbon certified for PFASNSF/ANSI 53 or 58, with PFPeA named on the listing

Understand water treatment technologies →

Commercial

No certified match for these concerns yet

Each card names which Duncan findings its current certification covers, and which it doesn't.

As an Amazon Associate, PurityMap earns from qualifying purchases. A product appears here only when a current certification record covers at least one identified concern; every concern stays listed. The retail offer is looked up afterwards and never changes which products appear or their order. Affiliate disclosure.

No product in our catalogue has verified certification for these concerns yet.

Is this right for my home?

Choose your situation

Your situation
Your path: I live in an older buildingLead from plumbing is the main question

Older buildings may have lead service lines, solder or fixtures. Duncan’s utility reported 10,938 service lines of unknown material in EPA’s inventory, so only a tap test tells you. Test first-draw water, then filter if needed.

Look forLead reduction: NSF/ANSI 53 (lead)
How to test your tap →
Your path: I care about PFASCheck what was tested

4 of 29 PFAS tested were detected in Duncan’s record (PFHxA 3.3 ng/L, PFBA 7.5 ng/L and PFHpA 3.4 ng/L, and more). If PFAS matters to you, a filter certification names each compound it covers.

Look forNSF/ANSI 53 or 58, with each compound you care about named on the listing
PFAS in Duncan →
Your path: My water tastes of chlorineThe disinfectant is not in this record

Most utilities keep chlorine or chloramine in the pipes. A carbon filter certified for taste and odor reduces either; your utility can tell you which it uses.

Look forNSF/ANSI 42 (chlorine taste and odor)
Water treatment technologies →
Your path: I have scale or hard waterHardness is not in this record

Your utility’s annual water quality report usually lists hardness; a test strip also measures it.

Look forSoftener: NSF/ANSI 44 (softeners)
Hard water explained →
Your path: I want the broadest reductionReverse osmosis at one tap

Reverse osmosis reduces many dissolved contaminants, including lead and minerals, at a single faucet, with some water sent to drain.

Look forNSF/ANSI 58
Compare treatments →
Questions

Duncan tap water FAQ

Follow Duncan’s water

Get one email when Duncan’s record changes.

Follow Duncan’s water →
Is Duncan tap water safe to drink?

PurityMap does not give a safe/unsafe verdict; it shows what the public records measured. For Duncan, PFAS were detected below their limits, and PFBA 7.5 ng/L, PFHpA 3.4 ng/L and PFPeA 3.8 ng/L with no federal or state limit. DUNCAN PUBLIC UTILITIES AUTHORITY (PWSID OK1010809) has a Purity Score of 88/100 (confidence: moderate), assessed at the water-system level and computed only from contaminants that were measured. Water can change in your own pipes, so a certified test is the only way to know what comes out of your tap. What we found →

Who provides tap water in Duncan?

DUNCAN PUBLIC UTILITIES AUTHORITY (PWS ID OK1010809) is the public water system on record for Duncan, Oklahoma, serving about 23,000 people. Confirm the utility on your water bill before acting on a specific finding. Water utility →

Where does Duncan get its drinking water?

Surface water (primary source of record in EPA SDWIS). Water utility →

Are PFAS "forever chemicals" in Duncan's water?

In EPA's UCMR 5 testing (2023-10-03 to 2024-07-10), PFHxA was detected at 3.3 ng/L, below the 400,000 ng/L state limit. PFBA (7.5 ng/L), PFHpA (3.4 ng/L) and PFPeA (3.8 ng/L) were also detected; they have no federal or state limit. What we found →

Is there lead in Duncan's tap water?

Lead is not in Duncan's current published record. Lead usually enters from a building's own pipes and fixtures, so a certified home test is the way to know yours. Your household →

What does the latest Duncan water report show?

PurityMap's current record for Duncan holds 31 findings: 1 above a reference, 1 detected within the reference, 3 detected with no limit and 26 not detected. Each finding links to its dated public record; a parameter that was never monitored is shown as pending, not as a pass. Records →

Data and sources

31 records, each traceable

  • EPA UCMR 5
  • EPA SDWIS (Lead & Copper Rule)
ContaminantMeasuredReferenceSampledSource
Lithium14.2 µg/L10 µg/L EPA health reference level (screening, not a legal limit)2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluorohexanoic acid (PFHxA)3.3 ng/L400,000 ng/L Michigan EGLE state MCL (strictest US state)2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluorobutanoic acid (PFBA)7.5 ng/LNo federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluoroheptanoic acid (PFHpA)3.4 ng/LNo federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluoropentanoic acid (PFPeA)3.8 ng/LNo federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)< 5 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)< 5 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)< 3 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)< 5 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
4,8-Dioxa-3H-perfluorononanoic acid (ADONA)< 3 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)< 2 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)< 5 ng/L (not detected)10 ng/L federal MCL (2024)2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Lead (90th percentile)Not detected15 µg/L federal action level2022–2024EPA SDWIS (Lead & Copper Rule) ↗ (opens in a new tab)
N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)< 5 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)< 6 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)< 20 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)< 3 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluoro-3-methoxypropanoic acid (PFMPA)< 4 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluoro-4-methoxybutanoic acid (PFMBA)< 3 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluorobutanesulfonic acid (PFBS)< 3 ng/L (not detected)2,000 ng/L EPA health advisory (screening, not a legal limit)2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluorodecanoic acid (PFDA)< 3 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluorododecanoic acid (PFDoA)< 3 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluoroheptanesulfonic acid (PFHpS)< 3 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluorohexanesulfonic acid (PFHxS)< 3 ng/L (not detected)10 ng/L federal MCL (2024)2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluorononanoic acid (PFNA)< 4 ng/L (not detected)10 ng/L federal MCL (2024)2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluorooctanesulfonic acid (PFOS)< 4 ng/L (not detected)4.0 ng/L federal MCL (2024)2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluorooctanoic acid (PFOA)< 4 ng/L (not detected)4.0 ng/L federal MCL (2024)2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluoropentanesulfonic acid (PFPeS)< 4 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluorotetradecanoic acid (PFTA)< 8 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluorotridecanoic acid (PFTrDA)< 7 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
Perfluoroundecanoic acid (PFUnA)< 2 ng/L (not detected)No federal or state limit; shown for transparency2023–2024EPA UCMR 5 ↗ (opens in a new tab)
  • UCMR5 Analytical Results

    UCMR5 Analytical Results: DUNCAN PUBLIC UTILITIES AUTHORITY (OK1010809)

    US EPA

    Published
    2026-10-15
    Newest sample
    2024-07-10
    Findings here
    30
  • State SDWIS Compliance Record

    Lead & Copper Rule 90th-percentile: DUNCAN PUBLIC UTILITIES AUTHORITY (OK1010809)

    US EPA SDWIS

    Published
    2026-10-13
    Newest sample
    2024
    Findings here
    1

Methodology: how we analyze water. Prepared with AI assistance and reviewed by the PurityMap Editorial Team before publication.

Methodology

How PurityMap reads Duncan’s water

  1. 01Source data

    EPA SDWIS, EPA UCMR 5 and utility reports, each dated and linked.

  2. 02Normalize

    Units converted to one basis; a non-detect kept distinct from zero.

  3. 03Classify

    Each result tagged by reference type: MCL, action level, screening level or aesthetic.

  4. 04Compare to the named reference

    Every value sits against its own reference, never a blended one.

  5. 05Score

    Measured subjects summarised at the water-system level; an open health-based violation caps the score.

  6. 06Match treatment

    Treatment is matched to what was found; a product is called certified only when its current certification names it.

What the Purity Score means: a summary of this water system’s published record, capped while a health-based violation is open. It is not a test of any tap. DUNCAN PUBLIC UTILITIES AUTHORITY · PWSID OK1010809 · Purity Score 88/100 (Good) · Confidence: moderate · Assessed at the water-system level

Full methodology →

Something off with your water's smell, color or taste?

Start with the hot-or-cold tap check. Where Duncan Public Utilities Authority reported something related, it's shown below.

ZIP codes in Duncan

Look up water quality by ZIP code →