Cobalt
Overview
Cobalt is a metal that reaches water by erosion of natural deposits and from industrial discharge. EPA monitored it nationwide in 2013 to 2015 and has set no limit for it.
In Florida, Cobalt was found in 13 community water systems serving about 615,994 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: Erosion of natural deposits; 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 Reference Concentration (UCMR 3), Contaminant Information Sheets for the Final CCL 4. EPA sets this on intermediate exposure. It is not a legal limit and no utility is required to meet it.
Health effects the EPA associates with it: EPA's reference concentration of 70 ppb is set on intermediate-duration non-cancer effects.
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
Reverse osmosis removes it, and cation exchange captures it as it does other dissolved metals.
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
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.