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Updated 2026-10-15
County water report

Denton County Water Quality: 11 Cities Ranked by the Records

Denton County, Texas: 11 city reports built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.

Find my systemOpen on the mapPrivate wells in Denton County
Across the county's systems

Highest result for each contaminant

One row per contaminant: the highest result any system in the county reported, against its limit. Open a row for the systems behind it.

LithiumDetected in 4 systems of 11 tested10 µg/L EPA health reference level (screening, not a legal limit) · US EPAHighest76.6 µg/L
Perfluorooctanoic acid (PFOA)Detected in 1 system of 11 tested4.0 ng/L federal MCL (2024) · US EPAHighest4.4 ng/L
  • TOWN OF FLOWER MOUND4.4 ng/LSample date: 2023-04-24 to 2024-08-28
  • ARGYLE WSCNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-02-21 to 2024-01-31
  • CITY OF CARROLLTONNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-08-19 to 2025-08-25
  • CITY OF DENTONNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-01-23 to 2023-10-23
  • CITY OF LEWISVILLENot detected · below 4.0 ng/L lab reporting limitSample date: 2024-05-22 to 2025-03-20
  • CITY OF ROANOKENot detected · below 4.0 ng/L lab reporting limitSample date: 2024-01-16 to 2024-10-08
  • CITY OF SANGERNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-04-08 to 2025-02-11
  • CITY OF THE COLONYNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-01-19 to 2024-03-06
  • LAKE CITIES MUNICIPAL UTILITY AUTHORITYNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-01-23 to 2024-10-10
  • TOWN OF LITTLE ELMNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-01-13 to 2025-09-22
  • TOWN OF PROVIDENCE VILLAGENot detected · below 4.0 ng/L lab reporting limitSample date: 2023-03-07 to 2025-07-15
Lead (90th percentile)Detected in 10 systems of 11 tested15 µg/L federal action level · US EPAHighest5.35 µg/L
Perfluorohexanesulfonic acid (PFHxS)Detected in 1 system of 11 tested10 ng/L federal MCL (2024) · US EPAHighest3.2 ng/L
  • CITY OF ROANOKE3.2 ng/LSample date: 2024-01-16 to 2024-10-08
  • ARGYLE WSCNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-02-21 to 2024-01-31
  • CITY OF CARROLLTONNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-08-19 to 2025-08-25
  • CITY OF DENTONNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-01-23 to 2023-10-23
  • CITY OF LEWISVILLENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-05-22 to 2025-03-20
  • CITY OF SANGERNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-04-08 to 2025-02-11
  • CITY OF THE COLONYNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-01-19 to 2024-03-06
  • LAKE CITIES MUNICIPAL UTILITY AUTHORITYNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-01-23 to 2024-10-10
  • TOWN OF FLOWER MOUNDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-24 to 2024-08-28
  • TOWN OF LITTLE ELMNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-13 to 2025-09-22
  • TOWN OF PROVIDENCE VILLAGENot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-07 to 2025-07-15
Perfluorobutanesulfonic acid (PFBS)Detected in 8 systems of 11 tested2,000 ng/L EPA health advisory (screening, not a legal limit) · US EPAHighest5.3 ng/L
Perfluorohexanoic acid (PFHxA)Detected in 9 systems of 11 tested400,000 ng/L Michigan EGLE state MCL (strictest US state) · Michigan EGLEHighest12.9 ng/L
Perfluorobutanoic acid (PFBA)Detected in 10 systems of 11 testedNo federal or state limit; shown for transparencyHighest77.2 ng/L
Perfluoroheptanoic acid (PFHpA)Detected in 1 system of 11 testedNo federal or state limit; shown for transparencyHighest3.1 ng/L
  • TOWN OF FLOWER MOUND3.1 ng/LSample date: 2023-04-24 to 2024-08-28
  • ARGYLE WSCNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-02-21 to 2024-01-31
  • CITY OF CARROLLTONNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-08-19 to 2025-08-25
  • CITY OF DENTONNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-01-23 to 2023-10-23
  • CITY OF LEWISVILLENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-05-22 to 2025-03-20
  • CITY OF ROANOKENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-01-16 to 2024-10-08
  • CITY OF SANGERNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-04-08 to 2025-02-11
  • CITY OF THE COLONYNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-01-19 to 2024-03-06
  • LAKE CITIES MUNICIPAL UTILITY AUTHORITYNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-01-23 to 2024-10-10
  • TOWN OF LITTLE ELMNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-13 to 2025-09-22
  • TOWN OF PROVIDENCE VILLAGENot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-07 to 2025-07-15
1 more contaminant detectedShow
Perfluoropentanoic acid (PFPeA)Detected in 9 systems of 11 testedNo federal or state limit; shown for transparencyHighest11.6 ng/L
22 PFAS tested, none detected in any systemShow

Tested in these 11 systems: ARGYLE WSC, CITY OF CARROLLTON, CITY OF DENTON, CITY OF LEWISVILLE, CITY OF ROANOKE, CITY OF SANGER, CITY OF THE COLONY, LAKE CITIES MUNICIPAL UTILITY AUTHORITY, TOWN OF FLOWER MOUND, TOWN OF LITTLE ELM, TOWN OF PROVIDENCE VILLAGE

  • 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
  • 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)
  • 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
  • 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)
  • 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)
  • 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
  • Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)
  • N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
  • N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
  • Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
  • Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
  • Perfluoro-3-methoxypropanoic acid (PFMPA)
  • Perfluoro-4-methoxybutanoic acid (PFMBA)
  • Perfluorodecanoic acid (PFDA)
  • Perfluorododecanoic acid (PFDoA)
  • Perfluoroheptanesulfonic acid (PFHpS)
  • Perfluorononanoic acid (PFNA)
  • Perfluorooctanesulfonic acid (PFOS)
  • Perfluoropentanesulfonic acid (PFPeS)
  • Perfluorotetradecanoic acid (PFTA)
  • Perfluorotridecanoic acid (PFTrDA)
  • Perfluoroundecanoic acid (PFUnA)
11 cities

Cities ranked by the records

Showing 6 of 11 cities · scores are system-level, not tap tests

Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no county score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works.

PFAS in Denton County1 of 11 city reports had a PFAS sample above a 2024 EPA limit
4.0 ng/L federal MCL · PFOS, ng/LPFAS in Texas
Lead

0of 11 cities above the 15 µg/L action level

Based on each system's 90th-percentile result. Lead from household plumbing isn't in this record.

Lead in Texas
Who supplies the county

Largest water systems

  1. DentonCITY OF DENTON · TX0610002
    150,037 served
  2. LewisvilleCITY OF LEWISVILLE · TX0610004
    140,880 served
  3. CarrolltonCITY OF CARROLLTON · TX0570034
    136,170 served
  4. Flower MoundTOWN OF FLOWER MOUND · TX0610023
    80,000 served
  5. The ColonyCITY OF THE COLONY · TX0610081
    45,367 served
  6. Little ElmTOWN OF LITTLE ELM · TX0610035
    43,348 served
  7. Lake DallasLAKE CITIES MUNICIPAL UTILITY AUTHORITY · TX0610029
    17,826 served
  8. ArgyleARGYLE WSC · TX0610019
    12,720 served
  9. SangerCITY OF SANGER · TX0610006
    10,166 served
  10. RoanokeCITY OF ROANOKE · TX0610008
    10,127 served
Questions

Frequently asked

How does Denton County tap water compare across cities?

PurityMap ranks 11 cities in Denton County by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Carrollton's main water system: CITY OF CARROLLTON · PWSID TX0570034 · Purity Score 100 (Excellent) · Confidence: moderate · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.

How many Denton County cities had a PFAS sample above a 2024 EPA limit?

1 of 11 Denton County city reports had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing, including Flower Mound (PFOA 4.4 ng/L). That limit is judged on a yearly average, and water systems have until 2029 to meet it, so a single sample is not a violation. PFAS were detected at any level in 10.

Is there lead in Denton County tap water?

Utilities report lead as a 90th-percentile result from home taps. 10 of 11 Denton County cities reported a value above zero, and none was above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.

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