ZIP Code 78665
High RiskPFAS above EPA limits detected
6 compounds exceed EPA Maximum Contaminant Levels in water serving this ZIP code. Standard pitcher filters like Brita do not remove PFAS. See filter recommendations below.
43
PFAS Detected
6
Above EPA Limits
9
Water Systems
310%
Highest % of MCL
Compounds Exceeding EPA Limits
PFOS Exceeds EPA limit
0 ppt MCL: 4 ppt 310% of limit
Detected: 12.40 ppt
PFNA Exceeds EPA limit
0 ppt MCL: 10 ppt 243% of limit
Detected: 24.30 ppt
PFOA Exceeds EPA limit
0 ppt MCL: 4 ppt 148% of limit
Detected: 5.90 ppt
MANVILLE WSC
TX2270033 High RiskWater Type
Groundwater
PFAS Detected
11
Above MCL
3
State
Texas
Data Period
2023–2025
PFAS Test Results
| Compound | Detected | vs. EPA Limit | EPA Limit | Status |
|---|---|---|---|---|
PFOS Perfluorooctane sulfonic acid | 12.40ppt | 310% of limit
| 4 ppt | ⚠ Exceeds MCL |
PFNA Perfluorononanoic acid | 24.30ppt | 243% of limit
| 10 ppt | ⚠ Exceeds MCL |
PFOA Perfluorooctanoic acid | 5.90ppt | 148% of limit
| 4 ppt | ⚠ Exceeds MCL |
PFHxS Perfluorohexane sulfonic acid | 7.00ppt | 70% of limit
| 10 ppt | Below limit |
lithium | 83800.00ppt | No federal limit | — | Unregulated |
PFBS Perfluorobutane sulfonic acid | 10.00ppt | No federal limit | — | Unregulated |
PFPeA Perfluoropentanoic acid | 9.10ppt | No federal limit | — | Unregulated |
PFHxA Perfluorohexanoic acid | 8.70ppt | No federal limit | — | Unregulated |
Show 3 more compounds detected at low levels
| PFBAPerfluorobutanoic acid | 7.40 ppt | No federal limit |
| PFHpAPerfluoroheptanoic acid | 4.30 ppt | No federal limit |
| PFUnAPerfluoroundecanoic acid | 2.70 ppt | No federal limit |
TRAVIS COUNTY WCID 18
TX2270083 Low LevelWater Type
Surface Water
PFAS Detected
2
Above MCL
0
State
Texas
Data Period
2023–2025
PFAS Test Results
| Compound | Detected | vs. EPA Limit | EPA Limit | Status |
|---|---|---|---|---|
PFBA Perfluorobutanoic acid | 8.20ppt | No federal limit | — | Unregulated |
PFPeA Perfluoropentanoic acid | 3.10ppt | No federal limit | — | Unregulated |
TRAVIS COUNTY WCID 10
TX2270182 High RiskWater Type
Surface Water
PFAS Detected
5
Above MCL
1
State
Texas
Data Period
2023–2025
PFAS Test Results
| Compound | Detected | vs. EPA Limit | EPA Limit | Status |
|---|---|---|---|---|
PFOS Perfluorooctane sulfonic acid | 5.50ppt | 138% of limit
| 4 ppt | ⚠ Exceeds MCL |
PFHxS Perfluorohexane sulfonic acid | 4.00ppt | 40% of limit
| 10 ppt | Below limit |
PFBA Perfluorobutanoic acid | 9.90ppt | No federal limit | — | Unregulated |
PFPeA Perfluoropentanoic acid | 3.40ppt | No federal limit | — | Unregulated |
PFBS Perfluorobutane sulfonic acid | 3.10ppt | No federal limit | — | Unregulated |
TRAVIS COUNTY MUD 18
TX2270403 Low LevelWater Type
Surface Water
PFAS Detected
1
Above MCL
0
State
Texas
Data Period
2023–2025
PFAS Test Results
| Compound | Detected | vs. EPA Limit | EPA Limit | Status |
|---|---|---|---|---|
PFBA Perfluorobutanoic acid | 8.60ppt | No federal limit | — | Unregulated |
CITY OF ROUND ROCK
TX2460003 ModerateWater Type
Groundwater
PFAS Detected
5
Above MCL
0
State
Texas
Data Period
2023–2025
PFAS Test Results
| Compound | Detected | vs. EPA Limit | EPA Limit | Status |
|---|---|---|---|---|
lithium | 13500.00ppt | No federal limit | — | Unregulated |
PFBS Perfluorobutane sulfonic acid | 6.70ppt | No federal limit | — | Unregulated |
PFPeA Perfluoropentanoic acid | 6.70ppt | No federal limit | — | Unregulated |
PFBA Perfluorobutanoic acid | 5.10ppt | No federal limit | — | Unregulated |
PFHxA Perfluorohexanoic acid | 3.70ppt | No federal limit | — | Unregulated |
JONAH WATER SUD
TX2460022 High RiskWater Type
Groundwater
PFAS Detected
8
Above MCL
2
State
Texas
Data Period
2023–2025
PFAS Test Results
| Compound | Detected | vs. EPA Limit | EPA Limit | Status |
|---|---|---|---|---|
PFOS Perfluorooctane sulfonic acid | 5.70ppt | 143% of limit
| 4 ppt | ⚠ Exceeds MCL |
PFOA Perfluorooctanoic acid | 5.10ppt | 128% of limit
| 4 ppt | ⚠ Exceeds MCL |
PFHxS Perfluorohexane sulfonic acid | 5.60ppt | 56% of limit
| 10 ppt | Below limit |
lithium | 38600.00ppt | No federal limit | — | Unregulated |
PFPeA Perfluoropentanoic acid | 21.20ppt | No federal limit | — | Unregulated |
PFBA Perfluorobutanoic acid | 15.80ppt | No federal limit | — | Unregulated |
PFBS Perfluorobutane sulfonic acid | 9.30ppt | No federal limit | — | Unregulated |
PFHxA Perfluorohexanoic acid | 9.20ppt | No federal limit | — | Unregulated |
WILLIAMSON COUNTY MUD 10
TX2460145 Low LevelWater Type
Surface Water
PFAS Detected
4
Above MCL
0
State
Texas
Data Period
2023–2025
PFAS Test Results
| Compound | Detected | vs. EPA Limit | EPA Limit | Status |
|---|---|---|---|---|
lithium | 16900.00ppt | No federal limit | — | Unregulated |
PFBA Perfluorobutanoic acid | 5.60ppt | No federal limit | — | Unregulated |
PFPeA Perfluoropentanoic acid | 3.80ppt | No federal limit | — | Unregulated |
PFBS Perfluorobutane sulfonic acid | 3.00ppt | No federal limit | — | Unregulated |
WILLIAMSON COUNTY WSID 3
TX2460152 Low LevelWater Type
Groundwater
PFAS Detected
4
Above MCL
0
State
Texas
Data Period
2023–2025
PFAS Test Results
| Compound | Detected | vs. EPA Limit | EPA Limit | Status |
|---|---|---|---|---|
PFNA Perfluorononanoic acid | 5.00ppt | 50% of limit
| 10 ppt | Below limit |
lithium | 71800.00ppt | No federal limit | — | Unregulated |
PFBS Perfluorobutane sulfonic acid | 3.50ppt | No federal limit | — | Unregulated |
PFPeA Perfluoropentanoic acid | 3.10ppt | No federal limit | — | Unregulated |
WILLIAMSON COUNTY MUD 11
TX2460159 Low LevelWater Type
Surface Water
PFAS Detected
3
Above MCL
0
State
Texas
Data Period
2023–2025
PFAS Test Results
| Compound | Detected | vs. EPA Limit | EPA Limit | Status |
|---|---|---|---|---|
lithium | 11600.00ppt | No federal limit | — | Unregulated |
PFBA Perfluorobutanoic acid | 5.60ppt | No federal limit | — | Unregulated |
PFPeA Perfluoropentanoic acid | 3.00ppt | No federal limit | — | Unregulated |
Note: ZIP code 78665 is served by 9 separate water utilities.
Results above show data for each system independently.
Data source: EPA Unregulated Contaminant Monitoring Rule, 5th cycle (UCMR 5) — January 2026 release.
UCMR 5 tested ~10,000 public water systems serving more than 25 people between 2023-2025 for 29 PFAS compounds.
Detection values represent the highest single-sample result measured at entry points to the distribution system.