Chlorate
Overview
Chlorate is a disinfection byproduct. It forms in the water itself, from chlorine dioxide or from hypochlorite solution that has degraded in storage, which means the treatment makes it rather than the source carrying it in. EPA monitored it nationwide in 2013 to 2015 and has set no limit for it.
In Florida, Chlorate was found in 201 community water systems serving about 17,057,070 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: Byproduct of drinking water disinfection.
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 chronic 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 210 ppb is set on chronic 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
No household filter removes it reliably. It is controlled at the plant, by how the disinfectant is made, dosed and stored.
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 201 systems that reported Chlorate.
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.