Tampa tap water: very hard water, PFOS samples up to 6.9 ppt (EPA limit 4)

Hardness is dissolved calcium and magnesium, picked up as water runs through rock. It isn’t a health issue (EPA has no limit for it). It’s what leaves white crust on faucets, spots on glasses and scale inside your water heater. It’s measured in grains per gallon (gpg); 1 gpg is about 17 mg of minerals in a liter.

Here: At 10.8 gpg, Tampa water is very hard, the 6th-hardest of the 34 systems we track. You’ll see scale on fixtures and inside appliances.

What to do: A water softener is the only whole-house system that removes hardness. Size it to your household so it doesn’t waste salt.

What the research says: Studies tie hard water to more soap use and scale. Observational studies link it with somewhat more eczema in babies, but in the largest trial a softener didn’t improve existing eczema. The studies →

PFAS are a family of thousands of manufactured chemicals used in many consumer and industrial products. They break down very slowly, which is why people call them "forever chemicals." PFOA and PFOS are the two EPA regulates most tightly. They’re measured in parts per trillion (ppt): 1 ppt is about one drop in 20 Olympic swimming pools.

Here: Tampa’s highest PFOS sample was 6.9 ppt, about 1.7 times EPA’s 4 ppt limit, the 6th-highest of the 40 we track. 11 of the 40 had a sample over the limit; 29 had none detected at all. These are samples from EPA’s 2023–25 testing, not a violation: utilities have until 2029 to get under the limit on a yearly average.

What to do: A filter on the tap you drink and cook from handles it. Look for reverse osmosis certified to NSF/ANSI 58, or carbon certified to NSF/ANSI 53, for PFOA and PFOS by name.

What the research says: EPA and the National Academies link PFOA and PFOS exposure to higher cholesterol, lower vaccine response, lower birth weight and some cancers, mostly over years of drinking the water. The studies →

Utilities add a small amount of chlorine, or chloramine (chlorine combined with a little ammonia), so germs can’t grow in the pipes on the way to your tap. EPA allows up to 4 milligrams per liter (mg/L) of either and says water within its standards can be used for drinking, cooking and bathing.

Here: Tampa uses chloramine, like 20 other systems we track. It lasts longer in pipes than chlorine and is harder to filter.

What to do: For taste, use catalytic carbon or a filter certified to NSF/ANSI 42 for chloramine. Fish tanks and home dialysis need it removed completely.

What the research says: Health agencies call these levels acceptable for drinking and bathing; dialysis and fish tanks are the exceptions. Studies haven’t shown shower chlorine harms skin or hair. The studies →

A health-based violation means the utility broke a federal drinking water rule tied to health: it went over a limit, or skipped a required treatment step. Missing a paperwork deadline doesn’t count.

Here: Tampa’s system had none in the five years through September 2026. That’s normal for a large system: 36 of the 40 we track had none.

What to do: Nothing to do.