Updated 2026-10-15

County water report

Collin County Water Quality: 11 Cities Ranked by the Records

Name: Collin County Water Quality Data (2026)
Creator: PurityMap
License: https://creativecommons.org/licenses/by/4.0/

Collin 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 system Open on the map Private wells in Collin 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 1 system of 11 tested10 µg/L EPA health reference level (screening, not a legal limit) · US EPAHighest31.9 µg/L

CITY OF ANNA31.9 µg/LSample date: 2025-02-04 to 2025-11-18
BEAR CREEK SUDNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-01-17 to 2024-10-09
CITY OF ALLENNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-02-22 to 2023-11-06
CITY OF CELINANot detected · below 9.0 µg/L lab reporting limitSample date: 2025-01-27 to 2025-10-30
CITY OF FRISCONot detected · below 9.0 µg/L lab reporting limitSample date: 2023-12-05 to 2024-09-04
CITY OF MCKINNEYNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-08-13 to 2025-05-13
CITY OF MELISSANot detected · below 9.0 µg/L lab reporting limitSample date: 2023-04-03 to 2024-01-23
CITY OF PLANONot detected · below 9.0 µg/L lab reporting limitSample date: 2025-02-18 to 2025-11-05
CITY OF PRINCETONNot detected · below 9.0 µg/L lab reporting limitSample date: 2025-03-17 to 2025-12-16
CITY OF WYLIENot detected · below 9.0 µg/L lab reporting limitSample date: 2023-04-13 to 2024-01-09
TOWN OF PROSPERNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-01-17 to 2023-10-11

Perfluorooctanesulfonic acid (PFOS)Detected in 1 system of 11 tested4.0 ng/L federal MCL (2024) · US EPAHighest4.7 ng/L

TOWN OF PROSPER4.7 ng/LSample date: 2023-04-17 to 2024-03-27
BEAR CREEK SUDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-01-17 to 2024-10-09
CITY OF ALLENNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-02-22 to 2023-11-06
CITY OF ANNANot detected · below 4.0 ng/L lab reporting limitSample date: 2025-02-04 to 2025-11-18
CITY OF CELINANot detected · below 4.0 ng/L lab reporting limitSample date: 2025-03-20 to 2025-09-17
CITY OF FRISCONot detected · below 4.0 ng/L lab reporting limitSample date: 2023-12-05 to 2024-09-04
CITY OF MCKINNEYNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-08-13 to 2025-05-13
CITY OF MELISSANot detected · below 4.0 ng/L lab reporting limitSample date: 2023-04-03 to 2024-01-23
CITY OF PLANONot detected · below 4.0 ng/L lab reporting limitSample date: 2025-02-18 to 2025-11-05
CITY OF PRINCETONNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-03-17 to 2025-12-16
CITY OF WYLIENot detected · below 4.0 ng/L lab reporting limitSample date: 2023-04-13 to 2024-02-08

Water hardnessDetected in 2 systemsAesthetic, no federal health limit · USGSHighest10.2 gpg

CITY OF FRISCO10.2 gpgReporting year: 2025
CITY OF PLANO8.7 gpgReporting year: 2025

Perfluorohexanesulfonic acid (PFHxS)Detected in 1 system of 11 tested10 ng/L federal MCL (2024) · US EPAHighest5.2 ng/L

TOWN OF PROSPER5.2 ng/LSample date: 2023-04-17 to 2024-03-27
BEAR CREEK SUDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-01-17 to 2024-10-09
CITY OF ALLENNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-02-22 to 2023-11-06
CITY OF ANNANot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-04 to 2025-11-18
CITY OF CELINANot detected · below 3.0 ng/L lab reporting limitSample date: 2025-03-20 to 2025-09-17
CITY OF FRISCONot detected · below 3.0 ng/L lab reporting limitSample date: 2023-12-05 to 2024-09-04
CITY OF MCKINNEYNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-08-13 to 2025-05-13
CITY OF MELISSANot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-03 to 2024-01-23
CITY OF PLANONot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-18 to 2025-11-05
CITY OF PRINCETONNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-03-17 to 2025-12-16
CITY OF WYLIENot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-13 to 2024-02-08

Total trihalomethanes (TTHM)Detected in 2 systems80 ppb federal MCL · US EPAHighest36 ppb

CITY OF FRISCO36 ppbReporting year: 2025
CITY OF MCKINNEY35.4 ppbReporting year: 2025

Haloacetic acids (HAA5)Detected in 2 systems60 ppb federal MCL · US EPAHighest22 ppb

CITY OF FRISCO22 ppbReporting year: 2025
CITY OF MCKINNEY20.5 ppbReporting year: 2025

CopperDetected in 1 system1.3 mg/L (action level) · US EPAHighest0.455 mg/L

CITY OF FRISCO0.455 mg/LReporting year: 2025

Lead (90th percentile)Detected in 10 systems of 11 tested15 µg/L federal action level · US EPAHighest1.98 µg/L

CITY OF CELINA1.98 µg/LMonitoring period: 2024–2026 (still open)
TOWN OF PROSPER1.98 µg/LMonitoring period: 2022–2024
CITY OF PRINCETON1.76 µg/LMonitoring period: 2026–2026 (still open)
CITY OF ALLEN1.7 µg/LMonitoring period: 2026–2026 (still open)
CITY OF PLANO1.68 µg/LMonitoring period: 2026–2026 (still open)
CITY OF MCKINNEY1.65 µg/LMonitoring period: 2026–2026 (still open)
CITY OF MELISSA1.43 µg/LMonitoring period: 2022–2024
CITY OF FRISCO1.4 µg/LMonitoring period: 2024–2026 (still open)
BEAR CREEK SUD1.12 µg/LMonitoring period: 2025–2025
CITY OF WYLIE1.03 µg/LMonitoring period: 2025–2025
CITY OF ANNANot detectedMonitoring period: 2026–2026 (still open)

8 more contaminants detectedShow

FluorideDetected in 1 system4.0 mg/L · US EPAHighest0.492 mg/L

CITY OF FRISCO0.492 mg/LReporting year: 2025

ArsenicDetected in 1 system0.010 mg/L · US EPAHighest0.001 mg/L

CITY OF FRISCO0.001 mg/LReporting year: 2025

NitrateDetected in 1 system10 mg/L · US EPAHighest0.866 mg/L

CITY OF FRISCO0.866 mg/LReporting year: 2025

Perfluorobutanesulfonic acid (PFBS)Detected in 6 systems of 11 tested2,000 ng/L EPA health advisory (screening, not a legal limit) · US EPAHighest6.6 ng/L

CITY OF WYLIE6.6 ng/LSample date: 2023-04-13 to 2024-02-08
TOWN OF PROSPER5.4 ng/LSample date: 2023-04-17 to 2024-03-27
BEAR CREEK SUD4.9 ng/LSample date: 2024-01-17 to 2024-10-09
CITY OF FRISCO4.7 ng/LSample date: 2023-12-05 to 2024-09-04
CITY OF ALLEN4.6 ng/LSample date: 2023-02-22 to 2023-11-06
CITY OF PLANO3.1 ng/LSample date: 2025-02-18 to 2025-11-05
CITY OF ANNANot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-04 to 2025-11-18
CITY OF CELINANot detected · below 3.0 ng/L lab reporting limitSample date: 2025-03-20 to 2025-09-17
CITY OF MCKINNEYNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-08-13 to 2025-05-13
CITY OF MELISSANot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-03 to 2024-01-23
CITY OF PRINCETONNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-03-17 to 2025-12-16

Perfluorohexanoic acid (PFHxA)Detected in 6 systems of 11 tested400,000 ng/L Michigan EGLE state MCL (strictest US state) · Michigan EGLEHighest8 ng/L

CITY OF WYLIE8 ng/LSample date: 2023-04-13 to 2024-02-08
TOWN OF PROSPER7.7 ng/LSample date: 2023-04-17 to 2024-03-27
CITY OF ALLEN7.4 ng/LSample date: 2023-02-22 to 2023-11-06
CITY OF FRISCO6.7 ng/LSample date: 2023-12-05 to 2024-09-04
BEAR CREEK SUD6.6 ng/LSample date: 2024-01-17 to 2024-10-09
CITY OF PLANO4.4 ng/LSample date: 2025-02-18 to 2025-11-05
CITY OF ANNANot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-04 to 2025-11-18
CITY OF CELINANot detected · below 3.0 ng/L lab reporting limitSample date: 2025-03-20 to 2025-09-17
CITY OF MCKINNEYNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-08-13 to 2025-05-13
CITY OF MELISSANot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-03 to 2024-01-23
CITY OF PRINCETONNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-03-17 to 2025-12-16

1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)Detected in 1 system of 11 testedNo federal or state limit; shown for transparencyHighest18 ng/L

BEAR CREEK SUD18 ng/LSample date: 2024-01-17 to 2024-10-09
CITY OF ALLENNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-02-22 to 2023-11-06
CITY OF ANNANot detected · below 5.0 ng/L lab reporting limitSample date: 2025-02-04 to 2025-11-18
CITY OF CELINANot detected · below 5.0 ng/L lab reporting limitSample date: 2025-03-20 to 2025-09-17
CITY OF FRISCONot detected · below 5.0 ng/L lab reporting limitSample date: 2023-12-05 to 2024-09-04
CITY OF MCKINNEYNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-08-13 to 2025-05-13
CITY OF MELISSANot detected · below 5.0 ng/L lab reporting limitSample date: 2023-04-03 to 2024-01-23
CITY OF PLANONot detected · below 5.0 ng/L lab reporting limitSample date: 2025-02-18 to 2025-11-05
CITY OF PRINCETONNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-03-17 to 2025-12-16
CITY OF WYLIENot detected · below 5.0 ng/L lab reporting limitSample date: 2023-04-13 to 2024-02-08
TOWN OF PROSPERNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-04-17 to 2024-03-27

Perfluorobutanoic acid (PFBA)Detected in 10 systems of 11 testedNo federal or state limit; shown for transparencyHighest13.8 ng/L

CITY OF FRISCO13.8 ng/LSample date: 2023-12-05 to 2024-09-04
BEAR CREEK SUD10.3 ng/LSample date: 2024-01-17 to 2024-10-09
CITY OF ALLEN9.3 ng/LSample date: 2023-02-22 to 2023-11-06
CITY OF MCKINNEY8.7 ng/LSample date: 2024-08-13 to 2025-05-13
CITY OF WYLIE8.6 ng/LSample date: 2023-04-13 to 2024-02-08
TOWN OF PROSPER8.4 ng/LSample date: 2023-04-17 to 2024-03-27
CITY OF MELISSA8 ng/LSample date: 2023-04-03 to 2024-01-23
CITY OF PLANO7.3 ng/LSample date: 2025-02-18 to 2025-11-05
CITY OF ANNA5.5 ng/LSample date: 2025-02-04 to 2025-11-18
CITY OF PRINCETON5.2 ng/LSample date: 2025-03-17 to 2025-12-16
CITY OF CELINANot detected · below 5.0 ng/L lab reporting limitSample date: 2025-03-20 to 2025-09-17

Perfluoropentanoic acid (PFPeA)Detected in 7 systems of 11 testedNo federal or state limit; shown for transparencyHighest9.1 ng/L

CITY OF CELINA9.1 ng/LSample date: 2025-03-20 to 2025-09-17
CITY OF WYLIE8.9 ng/LSample date: 2023-04-13 to 2024-02-08
BEAR CREEK SUD8.1 ng/LSample date: 2024-01-17 to 2024-10-09
CITY OF ALLEN8.1 ng/LSample date: 2023-02-22 to 2023-11-06
TOWN OF PROSPER7.8 ng/LSample date: 2023-04-17 to 2024-03-27
CITY OF FRISCO7.6 ng/LSample date: 2023-12-05 to 2024-09-04
CITY OF PLANO4.3 ng/LSample date: 2025-02-18 to 2025-11-05
CITY OF ANNANot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-04 to 2025-11-18
CITY OF MCKINNEYNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-08-13 to 2025-05-13
CITY OF MELISSANot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-03 to 2024-01-23
CITY OF PRINCETONNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-03-17 to 2025-12-16

22 PFAS tested, none detected in any systemShow

Tested in these 11 systems: BEAR CREEK SUD, CITY OF ALLEN, CITY OF ANNA, CITY OF CELINA, CITY OF FRISCO, CITY OF MCKINNEY, CITY OF MELISSA, CITY OF PLANO, CITY OF PRINCETON, CITY OF WYLIE, TOWN OF PROSPER

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)
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)
Perfluoroheptanoic acid (PFHpA)
Perfluorononanoic acid (PFNA)
Perfluorooctanoic acid (PFOA)
Perfluoropentanesulfonic acid (PFPeS)
Perfluorotetradecanoic acid (PFTA)
Perfluorotridecanoic acid (PFTrDA)
Perfluoroundecanoic acid (PFUnA)

11 cities

Cities ranked by the records

1
WylieCITY OF WYLIE
PFAS detected, within limitLead below action level
Open city report →
2
LavonBEAR CREEK SUD
PFAS detected, within limitLead below action level
Open city report →
3
PlanoCITY OF PLANO
PFAS detected, within limitLead below action level
Open city report →
4
AllenCITY OF ALLEN
PFAS detected, within limitLead below action level
Open city report →
5
CelinaCITY OF CELINA
PFAS detected, within limitLead below action level
Open city report →
6
PrincetonCITY OF PRINCETON
PFAS detected, within limitLead below action level
Open city report →
7
MelissaCITY OF MELISSA
PFAS detected, within limitLead below action level
Open city report →
8
AnnaCITY OF ANNA
PFAS detected, within limit
Open city report →
9
McKinneyCITY OF MCKINNEY
PFAS detected, within limitLead below action level
Open city report →
10
FriscoCITY OF FRISCO
PFAS detected, within limitLead below action level
Open city report →
11
ProsperTOWN OF PROSPER
PFAS sample above a limitLead below action level
Open city report →

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 Collin County1 of 11 city reports had a PFAS sample above a 2024 EPA limit

Prosper4.7 ng/L

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

Hard water

2cities report hardness · hardest Frisco, 10.2 gpg

2 of 2 are hard on the USGS scale. An aesthetic measure with no federal health limit.

Hard water explained

Who supplies the county

Largest water systems

PlanoCITY OF PLANO · TX0430007
292,059 served
FriscoCITY OF FRISCO · TX0430005
231,910 served
McKinneyCITY OF MCKINNEY · TX0430039
224,043 served
AllenCITY OF ALLEN · TX0430025
113,746 served
CelinaCITY OF CELINA · TX0430003
52,701 served
WylieCITY OF WYLIE · TX0430011
48,393 served
ProsperTOWN OF PROSPER · TX0430009
42,598 served
PrincetonCITY OF PRINCETON · TX0430008
37,019 served
MelissaCITY OF MELISSA · TX0430040
26,234 served
AnnaCITY OF ANNA · TX0430027
23,960 served

Questions

Frequently asked

How does Collin County tap water compare across cities?

PurityMap ranks 11 cities in Collin 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 Wylie's main water system: CITY OF WYLIE · PWSID TX0430011 · Purity Score 99 (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 Collin County cities had a PFAS sample above a 2024 EPA limit?

1 of 11 Collin County city reports had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing, including Prosper (PFOS 4.7 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 11.

Is there lead in Collin County tap water?

Utilities report lead as a 90th-percentile result from home taps. 10 of 11 Collin 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.

Does Collin County have hard water?

Hardness is published in utility water-quality reports for 2 Collin County cities on record; the hardest is Frisco at 10.2 grains per gallon. Hardness affects scale and appliances; it is not a health finding.

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