ZIP Code 93420
High RiskPFAS above EPA limits detected
2 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.
9
PFAS Detected
2
Above EPA Limits
2
Water Systems
170%
Highest % of MCL
Compounds Exceeding EPA Limits
PFOS Exceeds EPA limit
0 ppt MCL: 4 ppt 170% of limit
Detected: 6.80 ppt
PFOA Exceeds EPA limit
0 ppt MCL: 4 ppt 145% of limit
Detected: 5.80 ppt
ARROYO GRANDE, WATER DEPARTMENT
CA4010001 High RiskWater Type
Groundwater
PFAS Detected
7
Above MCL
2
State
California
Data Period
2023–2025
PFAS Test Results
| Compound | Detected | vs. EPA Limit | EPA Limit | Status |
|---|---|---|---|---|
PFOS Perfluorooctane sulfonic acid | 6.80ppt | 170% of limit
| 4 ppt | ⚠ Exceeds MCL |
PFOA Perfluorooctanoic acid | 5.80ppt | 145% of limit
| 4 ppt | ⚠ Exceeds MCL |
PFHxS Perfluorohexane sulfonic acid | 5.50ppt | 55% of limit
| 10 ppt | Below limit |
lithium | 60000.00ppt | No federal limit | — | Unregulated |
PFBS Perfluorobutane sulfonic acid | 11.00ppt | No federal limit | — | Unregulated |
PFPeA Perfluoropentanoic acid | 4.50ppt | No federal limit | — | Unregulated |
PFHxA Perfluorohexanoic acid | 3.50ppt | No federal limit | — | Unregulated |
GOLDEN STATE WATER COMPANY - NIPOMO
CA4010018 Low LevelWater Type
Groundwater
PFAS Detected
2
Above MCL
0
State
California
Data Period
2023–2025
PFAS Test Results
| Compound | Detected | vs. EPA Limit | EPA Limit | Status |
|---|---|---|---|---|
lithium | 10700.00ppt | No federal limit | — | Unregulated |
PFPeA Perfluoropentanoic acid | 3.20ppt | No federal limit | — | Unregulated |
Note: ZIP code 93420 is served by 2 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.