4:2 Fluorotelomer Sulfonic Acid (4:2 FTSA)
California Water Service (CWS) - Los Altos Suburban
NOTE: California Water Service (CWS) - Los Altos Suburban purchases water from Santa Clara Valley Water District which is required to test for 4:2 fluorotelomer sulfonic acid (4:2 ftsa). Sample information shown below was taken by Santa Clara Valley Water District.
4:2 Fluorotelomer Sulfonic Acid (4:2 FTSA) is a member of a class of chemicals called per- and polyfluoroalkyl substances or PFAS. These chemicals were used in the production of non-stick, stain repellent and chemically inert coatings. Click here to read more about perfluorinated chemicals.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | N/A | 0 | 0 | N/A |
| 2019 | N/A | 0 | 0 | N/A |
| 2020 | N/A | 0 | 0 | N/A |
| 2021 | N/A | 0 | 0 | N/A |
| 2022 | N/A | 0 | 0 | N/A |
| 2023 | ND | 42 | 0 | ND |
| 2024 | ND | 11 | 0 | ND |
ppt = parts per trillion
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 1 ppt
The EWG Health Guideline of 1 ppt for 4:2 fluorotelomer sulfonic acid (4:2 FTSA) was defined by EWG based on studies by Phillipe Grandjean of Harvard University and many other independent researchers who found reduced effectiveness of vaccines and adverse impacts on mammary gland development from exposure to PFOA and PFOS, the two PFAS most widely detected in drinking water.
ppt = parts per trillion
All test results
NOTE: California Water Service (CWS) - Los Altos Suburban purchases water from Santa Clara Valley Water District which is required to test for 4:2 fluorotelomer sulfonic acid (4:2 ftsa). Sample information shown below was taken by Santa Clara Valley Water District.
| Date | Lab ID | Result |
|---|---|---|
| 2023-02-23 | CA4310027_024_024-202302231053 | ND |
| 2023-05-10 | CA4310027_024_024-202305101114 | ND |
| 2023-05-10 | CA4310027_024_024-202305101118 | ND |
| 2023-08-09 | CA4310027_024_024-202308091047 | ND |
| 2023-11-15 | CA4310027_024_024-202311151019 | ND |