Chloramine and chlorine switches: what's happening and why
Reviewed by The Baylife Water Filtration Solutions team · Last reviewed · 5 min read
Key takeaways
- Some utilities that normally use chloramine switch to plain chlorine for a few weeks as routine distribution-system maintenance — it isn't a response to a contamination event.
- Tampa is switching to free chlorine September 14 – October 5, 2026, and back to chloramine on October 6. Pinellas County makes a similar switch twice a year.
- Hernando County, Brooksville, Plant City, Oldsmar, Dunedin and Tarpon Springs never switch — they're on straight chlorine year-round already, since each runs its own groundwater wells with no chloramine to begin with.
What chlorine and chloramine are
Both are EPA-compliant disinfectants used to keep water safe as it travels through the distribution system. Chlorine alone breaks down faster over distance; chloramine (chlorine combined with ammonia) holds its disinfecting power longer, which is why most utilities that serve large areas — including Hillsborough County Water Resources, Pinellas County Utilities, Pasco County Utilities, and the City of Tampa — use it as their everyday disinfectant. A handful of smaller municipal utilities within those same counties, including Plant City, Oldsmar, Dunedin and Tarpon Springs, run their own wells and use straight chlorine instead.
Why some utilities periodically switch back to chlorine
Utilities that normally run on chloramine periodically switch to straight chlorine for a few weeks at a time as part of routine maintenance of the distribution system — pipes, storage tanks, and the network in between. It's planned, temporary, and not a response to any contamination event or safety issue.
This year's dates
Tampa's 2026 switch runs free chlorine from September 14 through October 5, returning to chloramine on October 6 (City of Tampa water department notice). Hillsborough County systems that buy Tampa's water — East Lake, Fairview, Hershel Heights, Pebble Creek, and Seaboard — are affected too. Pinellas County makes a similar switch twice a year (Pinellas County Utilities FAQ).
What people notice during a switch
A stronger "pool water" chlorine taste or smell is the most common thing people notice — it's expected, and it fades once the switch ends. The City of Tampa itself recommends running a carbon filter on faucets and showerheads during the switch window.
The parts of our area that never switch
Hernando County (HCUD), the City of Brooksville, and the cities of Plant City, Oldsmar, Dunedin and Tarpon Springs all draw their water from their own groundwater wells and disinfect with straight chlorine year-round — they were never on chloramine to begin with, so there's no seasonal switch to notice.
What kind of filtration handles each
Ordinary carbon filters handle chlorine reasonably well but struggle with chloramine, which needs longer contact time with catalytic carbon to break down. Our whole-home filtration guide covers what's actually built for chloramine, versus a standard pitcher filter that isn't.