PFAS ("forever chemicals")
4:2 Fluorotelomer sulfonic acid (4:2 FTS) in U.S. tap water
22 public water systems across 5 U.S. states report 4:2 Fluorotelomer sulfonic acid (4:2 FTS) in their annual Consumer Confidence Report. None currently sit at or above the federal limit.
What it is
4:2 fluorotelomer sulfonic acid, a PFAS-related compound.
Why it's regulated
Monitored under EPA rules as part of broad PFAS surveillance.
Within the federal limit (22)
| Water system | Measured |
|---|---|
| Brown Deer, WI 2024 annual report | Not detected ug/L |
| Butler, WI 2024 annual report | Not detected ug/L |
| Chandler, AZ 2024 annual report | 0 ng/L |
| Dallas, TX 2024 annual report | Not detected ng/L |
| Franklin, WI 2024 annual report | Not detected ug/L |
| Greendale, WI 2024 annual report | Not detected ug/L |
| Greenfield, WI 2024 annual report | Not detected ug/L |
| Hales Corners, WI 2024 annual report | Not detected ug/L |
| Menomonee Falls, WI 2024 annual report | Not detected ug/L |
| Mequon, WI 2024 annual report | Not detected ug/L |
| Milwaukee, WI 2024 annual report | Not detected ug/L |
| New Berlin, WI 2024 annual report | Not detected ug/L |
| Pasadena, CA 2023 annual report | Not detected ug/L |
| Salem, OR 2023 annual report | Not detected ug/L |
| Santa Clarita, CA 2024 annual report | Not detected ug/L |
| Shorewood, WI 2024 annual report | Not detected ug/L |
| St. Francis, WI 2024 annual report | Not detected ug/L |
| Thiensville, WI 2024 annual report | Not detected ug/L |
| Tracy, CA 2024 annual report | Not detected |
| Waukesha, WI 2024 annual report | Not detected ug/L |
| Wauwatosa, WI 2024 annual report | Not detected ug/L |
| West Allis, WI 2024 annual report | Not detected ug/L |
Frequently asked
+What is 4:2 Fluorotelomer sulfonic acid (4:2 FTS)?
4:2 fluorotelomer sulfonic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
+What is the federal limit for 4:2 Fluorotelomer sulfonic acid (4:2 FTS) in drinking water?
The federal MCL for 4:2 Fluorotelomer sulfonic acid (4:2 FTS) is 3 ng/L. The EPA enforces this against the regulated reporting statistic (typically a running annual average or 90th percentile), not a single-sample spike.
+How many U.S. water systems have 4:2 Fluorotelomer sulfonic acid (4:2 FTS) over the federal limit?
Zero of the 22 public water systems in The Water Map dataset currently report 4:2 Fluorotelomer sulfonic acid (4:2 FTS) at or above its federal limit.
+How can I check if 4:2 Fluorotelomer sulfonic acid (4:2 FTS) is in my city's tap water?
Search your city on The Water Map (https://www.thewatermap.com/) or browse the list on this page. Every U.S. public water utility is required to publish an annual Consumer Confidence Report that lists every contaminant it measured, including 4:2 Fluorotelomer sulfonic acid (4:2 FTS).
See 4:2 Fluorotelomer sulfonic acid (4:2 FTS) on the map
Color-coded by status across the whole country.
Open the map →