Tap water report · updated November 2026
Miami tap water: PFOS samples up to 33.0 ppt (EPA limit 4)
What’s in the water Miami-Dade Water and Sewer Department delivers to 2.4 million people, from national testing by the U.S. Environmental Protection Agency (EPA) and the utility’s own report.
Short answer
Miami-Dade Water and Sewer Department’s annual water quality report doesn’t include a hardness figure, so there’s no published number for Miami. Ask the utility, or a home test strip gives you one in a minute. The U.S. Environmental Protection Agency’s (EPA’s) 2023–24 testing found PFOA and PFOS, the two PFAS “forever chemicals” EPA limits most tightly, at 14.0 and 33.0 parts per trillion (ppt) in its highest samples, above the 4 ppt limit utilities must meet by 2029. The system had no health-based violations in the five years through September 2026. Of the 40 large US water systems The Water Monitor tracks, Miami has the highest PFAS sample.
Sources: EPA UCMR 5, EPA SDWIS 2026Q3 · Sources and method
How Miami compares with the 40 systems we track
PFOA / PFOS
1st highest
of 11 that detected any
Size
6th largest
of 40 by people served
01 · What it means
What these readings mean for your home
Each reading in plain English: what it is, how Miami compares with the other systems we track, and whether there’s anything to do. The tags follow EPA’s limits and reference levels where EPA has one; for hardness, which has no EPA limit, they follow the U.S. Geological Survey (USGS) scale and Minnesota’s health department. New to the acronyms? Every term, in plain English.
Hardness
Worth knowingHardness is dissolved calcium and magnesium. It isn’t a health issue, but it decides whether a softener is worth buying. It’s measured in grains per gallon (gpg).
Here: Hardness isn’t in the Miami-Dade Water and Sewer Department annual water quality report, so there’s no published number for Miami. You can ask the utility, or test it yourself.
What to do: A hardness test strip or a lab test gives you the number in minutes. Then use the sizing calculator to see whether a softener makes sense.
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 →
Learn more →PFAS (PFOA and PFOS)
Worth acting onPFAS 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: Miami’s highest PFOS sample was 33.0 ppt, about 8 times EPA’s 4 ppt limit, and the highest of all 40 systems we track. 11 of the 40 had a sample over the limit; 29 had none detected at all. These are samples from EPA’s 2023–24 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 →
Learn more →Disinfectant
Nothing to doUtilities 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: Miami 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 →
Learn more →Health-based violations
Nothing to doA 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: Miami’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.
Learn more →How Miami compares: highest PFOA or PFOS sample
Parts per trillion (ppt), from EPA’s 2023–25 testing. The dashed line is EPA’s limit of 4.
- Miami33.0 PFOS
- El Paso8.5 PFOS
- Fort Worth8.3 PFOA
- Philadelphia8.1 PFOA
- Louisville7.5 PFOA
- Tampa6.9 PFOS
- Dallas6.3 PFOA
- San Jose6.2 PFOS
- Cincinnati6.1 PFOS
- Columbus5.3 PFOA
- Austin4.8 PFOS
If you live in Miami
- Get a hardness number It isn’t in the utility’s annual report. A test strip gives you one, and tells you whether a softener is worth it.
- Drinking water filters listed for PFOA and PFOS Under-sink systems with a public NSF, WQA or IAPMO listing, and what they cost.
- Whole-house filters for chloramine Miami uses chloramine, which ordinary carbon removes slowly. What to look for and what it costs.
02 · The full results
Every PFAS result EPA recorded
In EPA’s national testing (sampled 2023 to 2024), Miami’s highest samples reached PFOA and PFOS, the two PFAS “forever chemicals” EPA limits most tightly, at 14.0 and 33.0 ppt, above EPA’s 4 ppt limit. These are individual samples, not a compliance finding: water systems have until 2029 to meet the limit, judged on a yearly average.
Results from EPA’s national testing program (UCMR 5) for Miami-Dade Water and Sewer Department, 4 sampling points, November 2023 to May 2024. Concentrations in parts per trillion (ppt).
| Chemical | Samples | Detected | Highest | EPA limit |
|---|---|---|---|---|
| PFOA (perfluorooctanoic acid) | 8 | 6 | 14.0 | 4 |
| PFOS (perfluorooctane sulfonic acid) | 8 | 6 | 33.0 | 4 |
| PFHxS | 8 | 3 | 9.4 | 10 |
| PFNA | 8 | 2 | 6.5 | 10 |
| HFPO-DA (GenX) | 8 | 0 | none | 10 |
"None" means every sample was under EPA’s reporting level (4 ppt for PFOA). PFHxS, PFNA and HFPO-DA (GenX) are three other PFAS chemicals; EPA proposed removing their limits in May 2026, and that isn’t final.
03 · Where it comes from
The source, and who else drinks it
WASD’s source is groundwater from wells that draw mainly from the Biscayne Aquifer, with a limited number of wells in the Floridan Aquifer, and the main system is fed by the Alexander Orr, Jr., John E. Preston and Hialeah plants plus the Hialeah Reverse Osmosis plant, which treats brackish Upper Floridan Aquifer water.
Miami-Dade Water and Sewer Department serves about 2.4 million people directly, and 14 other water systems buy water from it, serving about 581,314 more. If you live in one of them, most of what’s on this page describes your water too, though hardness and disinfectant can change if your system blends in its own wells.
WASD’s three regional plants stopped adding fluoride on June 6, 2025, under County Resolution R-370-25 and Florida Senate Bill 700.
Miami’s water system had no health-based violations in the five years through September 2026, according to EPA’s federal database.
Largest systems that buy from Miami-Dade Water and Sewer Department
- Hialeah, City of238,000
- Miami Beach, City of100,000
- North Miami, City of89,349
- Homestead, City of80,000
- Hialeah Gardens22,200
- Opa Locka, City of16,479
- West Miami, City of8,500
- North Bay Village, City of8,317
- Bay Harbor Islands Town of6,000
- Surfside, Town of5,744
From EPA’s federal drinking water database (SDWIS), 2026Q3: community systems with an active connection buying from FL4130871. Population served.
ZIP codes Miami-Dade Water and Sewer Department reports serving (73)
33031 · 33032 · 33033 · 33101 · 33109 · 33116 · 33122 · 33125 · 33126 · 33127 · 33128 · 33129 · 33130 · 33131 · 33132 · 33133 · 33134 · 33135 · 33136 · 33137 · 33138 · 33139 · 33140 · 33141 · 33142 · 33143 · 33144 · 33145 · 33146 · 33147 · 33149 · 33150 · 33151 · 33152 · 33153 · 33154 · 33155 · 33156 · 33157 · 33158 · 33160 · 33161 · 33162 · 33165 · 33166 · 33167 · 33168 · 33169 · 33170 · 33172 · 33173 · 33174 · 33175 · 33176 · 33177 · 33178 · 33179 · 33180 · 33181 · 33182 · 33183 · 33184 · 33185 · 33186 · 33187 · 33189 · 33190 · 33192 · 33193 · 33194 · 33196 · 33197 · 33283
From EPA’s UCMR 5 ZIP file. A ZIP can be served by more than one system; your water bill names yours. Look up any ZIP.
04 · Questions
Miami water questions
Is Miami tap water safe to drink?
The U.S. Environmental Protection Agency (EPA) doesn’t grade a city’s tap water as safe or unsafe; it sets limits and records violations. By that record, Miami’s water system had no health-based violations of federal drinking water rules in the five years through September 2026. Separately, EPA’s 2023–24 testing found PFOA or PFOS (two PFAS “forever chemicals”) samples above the 4 parts per trillion (ppt) limit that utilities must meet, on a yearly average, by 2029. A filter certified to NSF/ANSI 53 or 58 for PFOA and PFOS addresses it at the tap.
Is Miami tap water hard?
Miami-Dade Water and Sewer Department’s annual water quality report doesn’t include a hardness figure, so there’s no published number for Miami. Ask the utility, or a home test strip gives you one in a minute.
Does Miami tap water have PFAS?
In the U.S. Environmental Protection Agency’s (EPA’s) national testing (sampled 2023 to 2024), Miami’s highest samples reached PFOA and PFOS, the two PFAS “forever chemicals” EPA limits most tightly, at 14.0 and 33.0 parts per trillion (ppt), above EPA’s 4 ppt limit. These are individual samples, not a compliance finding: water systems have until 2029 to meet the limit, judged on a yearly average.
Does Miami use chlorine or chloramine?
Chloramine. Miami-Dade Water and Sewer Department (WASD) says in its 2025 report that ammonia is added to combine with chlorine and form chloramine, and its table lists chloramines for the Main System at 2.5 parts per million (ppm; range: not detected to 4.0); the separate South Dade system uses chlorine.
Has Miami’s water system had violations?
Miami’s water system had no health-based violations in the five years through September 2026, according to the U.S. Environmental Protection Agency’s (EPA’s) federal database.
Nearest cities we cover
Sources
- 01Miami-Dade Water and Sewer Department water quality report (checked for hardness), read 2026-11-04
- 02Miami-Dade Water and Sewer Department (source water)
- 03Miami-Dade Water and Sewer Department (disinfectant)
- 04EPA, Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) occurrence data, file posted 2026-10-15
- 05EPA, Safe Drinking Water Information System via ECHO, 2026Q3 file
- 06EPA, PFAS National Primary Drinking Water Regulation, 89 FR 32532
- 07USGS Water Science School, "Hardness of Water"
EPA system ID FL4130871 · Miami-Dade Water and Sewer Department