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
What this means for you
One or more PFAS compounds were measured above the EPA's enforceable drinking water limit at a utility serving ZIP 78665. The EPA set these limits because long-term exposure at higher concentrations is associated with health effects including immune suppression, thyroid changes, and cancer risk increases. Standard pitcher filters (Brita, PUR) are not certified to remove PFAS. The most reliable at-home options are under-sink reverse osmosis systems or activated carbon block filters with an NSF/ANSI 58 certification specifically listing PFOA/PFOS reduction. Your water utility is required to bring levels into compliance by 2029 — filtering at the tap is the practical interim step if you'd like additional protection now.
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.
About this data
Source
EPA UCMR 5 (Unregulated Contaminant Monitoring Rule, 5th cycle)
Data released
January 2026
Sampling period
January 2023 – December 2025
Systems tested
~10,000 public water systems serving > 25 people
Water systems (PWSID)
TX2270033, TX2270083, TX2270182, TX2270403, TX2460003, TX2460022, TX2460145, TX2460152, TX2460159
Detection threshold (MRL)
~1.5–2 ppt — "Not detected" means below this floor, not zero
Values shown are the highest single-sample concentration measured at entry points to the distribution system. Results reflect water quality at the treatment plant — aging pipes, building plumbing, and on-site storage can affect what actually reaches your tap.