Williamson County Water Quality: 5 Cities Ranked by the Records
Williamson County, Texas: 5 city reports built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.
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 3 systems of 5 tested10 µg/L EPA health reference level (screening, not a legal limit) · US EPAHighest34.8 µg/L
- CITY OF HUTTO34.8 µg/LSample date: 2023-10-10 to 2024-07-16
- CITY OF GEORGETOWN17.4 µg/LSample date: 2023-06-14 to 2024-12-10
- CITY OF ROUND ROCK13.5 µg/LSample date: 2024-10-23 to 2025-07-14
- CITY OF CEDAR PARKNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-05-13 to 2025-02-27
- CITY OF TAYLORNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-10-26 to 2024-07-17
Perfluorooctanesulfonic acid (PFOS)Detected in 1 system of 5 tested4.0 ng/L federal MCL (2024) · US EPAHighest5.7 ng/L
- CITY OF GEORGETOWN5.7 ng/LSample date: 2023-06-14 to 2024-12-10
- CITY OF CEDAR PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-05-13 to 2025-02-27
- CITY OF HUTTONot detected · below 4.0 ng/L lab reporting limitSample date: 2023-10-10 to 2024-07-16
- CITY OF ROUND ROCKNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-10-23 to 2025-07-14
- CITY OF TAYLORNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-10-26 to 2024-07-17
Perfluorooctanoic acid (PFOA)Detected in 2 systems of 5 tested4.0 ng/L federal MCL (2024) · US EPAHighest5 ng/L
- CITY OF TAYLOR5 ng/LSample date: 2023-10-26 to 2024-07-17
- CITY OF GEORGETOWN4.9 ng/LSample date: 2023-06-14 to 2024-12-10
- CITY OF CEDAR PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-05-13 to 2025-02-27
- CITY OF HUTTONot detected · below 4.0 ng/L lab reporting limitSample date: 2023-10-10 to 2024-07-16
- CITY OF ROUND ROCKNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-10-23 to 2025-07-14
Water hardnessDetected in 1 systemAesthetic, no federal health limit · USGSHighest15.1 gpg
- CITY OF ROUND ROCK15.1 gpgReporting year: 2025
Perfluorohexanesulfonic acid (PFHxS)Detected in 1 system of 5 tested10 ng/L federal MCL (2024) · US EPAHighest4.7 ng/L
- CITY OF GEORGETOWN4.7 ng/LSample date: 2023-06-14 to 2024-12-10
- CITY OF CEDAR PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-05-13 to 2025-02-27
- CITY OF HUTTONot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-10 to 2024-07-16
- CITY OF ROUND ROCKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-10-23 to 2025-07-14
- CITY OF TAYLORNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-26 to 2024-07-17
Lead (90th percentile)Detected in 4 systems of 5 tested15 µg/L federal action level · US EPAHighest5.05 µg/L
- CITY OF ROUND ROCK5.05 µg/LMonitoring period: 2021–2023
- CITY OF GEORGETOWN4.81 µg/LMonitoring period: 2024–2026 (still open)
- CITY OF CEDAR PARK2.77 µg/LMonitoring period: 2024–2026 (still open)
- CITY OF TAYLOR1.93 µg/LMonitoring period: 2023–2025
- CITY OF HUTTONot detectedMonitoring period: 2024–2026 (still open)
Perfluorobutanesulfonic acid (PFBS)Detected in 3 systems of 5 tested2,000 ng/L EPA health advisory (screening, not a legal limit) · US EPAHighest9.6 ng/L
- CITY OF GEORGETOWN9.6 ng/LSample date: 2023-06-14 to 2024-12-10
- CITY OF TAYLOR9.4 ng/LSample date: 2023-10-26 to 2024-07-17
- CITY OF ROUND ROCK6.7 ng/LSample date: 2024-10-23 to 2025-07-14
- CITY OF CEDAR PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-05-13 to 2025-02-27
- CITY OF HUTTONot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-10 to 2024-07-16
Perfluorohexanoic acid (PFHxA)Detected in 3 systems of 5 tested400,000 ng/L Michigan EGLE state MCL (strictest US state) · Michigan EGLEHighest10.1 ng/L
- CITY OF GEORGETOWN10.1 ng/LSample date: 2023-06-14 to 2024-12-10
- CITY OF TAYLOR8.9 ng/LSample date: 2023-10-26 to 2024-07-17
- CITY OF ROUND ROCK3.7 ng/LSample date: 2024-10-23 to 2025-07-14
- CITY OF CEDAR PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-05-13 to 2025-02-27
- CITY OF HUTTONot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-10 to 2024-07-16
2 more contaminants detectedShow
Perfluorobutanoic acid (PFBA)Detected in 4 systems of 5 testedNo federal or state limit; shown for transparencyHighest33.8 ng/L
- CITY OF GEORGETOWN33.8 ng/LSample date: 2023-06-14 to 2024-12-10
- CITY OF TAYLOR10.3 ng/LSample date: 2023-10-26 to 2024-07-17
- CITY OF ROUND ROCK5.1 ng/LSample date: 2024-10-23 to 2025-07-14
- CITY OF CEDAR PARK5 ng/LSample date: 2024-05-13 to 2025-02-27
- CITY OF HUTTONot detected · below 5.0 ng/L lab reporting limitSample date: 2023-10-10 to 2024-07-16
Perfluoropentanoic acid (PFPeA)Detected in 3 systems of 5 testedNo federal or state limit; shown for transparencyHighest18.8 ng/L
- CITY OF TAYLOR18.8 ng/LSample date: 2023-10-26 to 2024-07-17
- CITY OF GEORGETOWN18.7 ng/LSample date: 2023-06-14 to 2024-12-10
- CITY OF ROUND ROCK6.7 ng/LSample date: 2024-10-23 to 2025-07-14
- CITY OF CEDAR PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-05-13 to 2025-02-27
- CITY OF HUTTONot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-10 to 2024-07-16
22 PFAS tested, none detected in any systemShow
Tested in these 5 systems: CITY OF CEDAR PARK, CITY OF GEORGETOWN, CITY OF HUTTO, CITY OF ROUND ROCK, CITY OF TAYLOR
- 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)
- Perfluoroheptanoic acid (PFHpA)
- Perfluorononanoic acid (PFNA)
- Perfluoropentanesulfonic acid (PFPeS)
- Perfluorotetradecanoic acid (PFTA)
- Perfluorotridecanoic acid (PFTrDA)
- Perfluoroundecanoic acid (PFUnA)
Cities ranked by the records
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.
0of 5 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 Texas1city reports hardness · Round Rock, 15.1 gpg
Hard on the USGS scale. An aesthetic measure with no federal health limit.
Hard water explainedLargest water systems
- GeorgetownCITY OF GEORGETOWN · TX2460001191,639 served
- Round RockCITY OF ROUND ROCK · TX2460003130,662 served
- Cedar ParkCITY OF CEDAR PARK · TX246000986,939 served
- HuttoCITY OF HUTTO · TX246000729,580 served
- TaylorCITY OF TAYLOR · TX246000420,622 served
Frequently asked
How does Williamson County tap water compare across cities?
PurityMap ranks 5 cities in Williamson 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 Hutto's main water system: CITY OF HUTTO · PWSID TX2460007 · 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 Williamson County cities had a PFAS sample above a 2024 EPA limit?
2 of 5 Williamson County city reports had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing, including Georgetown (PFOS 5.7 ng/L), Taylor (PFOA 5 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 4.
Is there lead in Williamson County tap water?
Utilities report lead as a 90th-percentile result from home taps. 4 of 5 Williamson 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 Williamson County have hard water?
Hardness is published in utility water-quality reports for 1 Williamson County city on record; the hardest is Round Rock at 15.1 grains per gallon. Hardness affects scale and appliances; it is not a health finding.
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