PFBS
Overview
Perfluorobutanesulfonic acid, a shorter-chain PFAS introduced as a replacement for PFOS. It has no federal limit of its own, but EPA's 2024 rule counts it toward a Hazard Index that limits mixtures of several PFAS together.
In Florida, PFBS was found in 139 community water systems serving about 10,632,742 people. Nobody has set a legal limit for it, so no reading here counts as an exceedance and no utility is required to do anything about it.
Where it comes from: Replacement chemistry for PFOS in stain and water repellents; firefighting foam; industrial discharge.
The standards
Enforceable. A utility must stay at or under this.
Health-based, not enforceable. Often lower than the limit, sometimes zero.
EPA lifetime drinking water health advisory (2022), EPA Drinking Water Health Advisory: Perfluorobutane Sulfonic Acid and Related Compound Potassium Perfluorobutane Sulfonate, EPA 822-R-22-004, June 2022. EPA published this for a lifetime of daily exposure, including during pregnancy, from animal studies of oral exposure. It is not a legal limit and no utility is required to meet it.
Health effects the EPA associates with it: EPA links PFAS exposure to decreased immune response, increased cholesterol, and developmental effects in infants and children.
The health goal is set on health alone. The legal limit is set as close to it as is technically and economically feasible, so treatment cost and available technology are written into the number a utility is measured against. A system at or under the limit is meeting the standard it is required to meet. Both numbers are shown so the distance between them is visible.
What removes it
Anion exchange and reverse osmosis handle it better than carbon does. Short-chain PFAS break through activated carbon sooner than long-chain ones, so carbon sized for PFOA will exhaust early against PFBS.
Treatment guidance describes the methods generally used for this contaminant. What your own tap actually carries depends on your plumbing and your service line as much as on the utility, which is what a test at the house tells you and an annual report cannot.
Where in Florida
Highest reported levels
Showing the 25 highest of 139 systems that reported PFBS.
Data Sources
These figures describe water as delivered by each utility, not what your home’s plumbing adds after it arrives. Informational; not a substitute for testing your own tap.