THE RIGANO WATER INSTITUTE
How to use this map: type your ZIP (top-left) or tap your neighborhood → read the verdict + Current Evidence bars → then walk the 6 numbered questions down the left edge. Toggle any dataset in the Map layers panel (bottom right) — and click any colored marker for the full detail behind it. Got it ×
Zoom in to reveal capture zones → wells → schools → samples
◍ The moving purple is PFAS in the groundwater — being pulled into the wells that supply your tap.
The contamination, over time1970
Map layers · tap to toggle
PUBLIC WATER RECORDUPDATED JULY 2026
MIAMI-DADE COUNTY
25.76°N 80.19°W · FLORIDA

What’s in your tap water?

Every public water system in Miami-Dade now runs over the federal PFAS limit — “forever chemicals” linked to thyroid disease, cancer and harm to children.
A 0–100 rating, read from your water system’s own EPA-reported record. Nothing sold. No email.
What PFAS is, how it builds up & who’s most at risk ▼
Read the county overview ▸
Primary sources only — the utilities’ own reports, EPA rules, and peer-reviewed studies. Updated July 2026 · a living document: when the evidence changes, our reading changes. Where a number is uncertain, we say so.
Flyover video transcript: Miami’s drinking water comes from these wells — the Biscayne Aquifer, right below your feet. These wells have been contaminated (Miami-Dade County record, 2019–2025). The red: PFAS contamination — “forever chemicals” from military-grade firefighting foam, measured in parts per trillion. Fire crews sprayed the foam, then washed it into the sewers — airports, fire-training sites, crash scenes (FDEP and county record). The chemicals soaked into the aquifer our drinking-water wells draw from — fire-academy groundwater reached 22,980 ppt (source water, not the tap). Groundwater moves east; pumping wells draw it in. Every system tested in Miami-Dade now exceeds the federal PFAS limit — Miami-Dade 17 of 17, Broward 21 of 21 (EPA sampling, single-sample maximum). Thyroid cancer runs about 40% above the U.S. rate county-wide, and is highest on the airport’s foam corridor — North Bay Village 36.3, Miami Springs 30.6, Doral 28.5 per 100,000. Living within 5 km of a PFAS site is associated with higher thyroid-cancer risk (University of Miami, Sylvester, 2025). The county settled with the foam makers, expecting $199 million; its own cleanup estimate is up to $3 billion. Proven solutions already exist: anion exchange plus reverse osmosis, combined — a Brita or fridge filter is not enough.
First: what is PFAS — and how does it reach your tap?
PFAS are man-made “forever chemicals” — they don’t break down in nature, or in the body. For 50+ years they’ve been the active ingredient in the firefighting foam (AFFF) sprayed at Miami International Airport and local fire-training grounds. That foam soaked into the ground, reached the aquifer our wells draw from, and now turns up in the water that reaches homes.
Aquifer
Plant
Main
Your tap
Your body
And once you drink PFAS, your body can’t clear it any better than the plant filtered it out — it builds up in your blood, year after year.
MethodsDataCorrectionsAbout
Updated July 2026 · a living document — when the evidence changes, our reading changes.
Primary sources only: the utilities’ own reports, EPA rules, and peer-reviewed studies.

Miami’s numbers, against every benchmark

The two federally regulated compounds in Miami-Dade Main System finished water, next to each yardstick. No adjectives — you decide.
CompoundReported 20252024 legal limit2022 health advisoryHealth goal
PFOS33 ppt40.020
PFOA13 ppt40.0040
4 PPT LIMITPFOS33 pptPFOA13 ppt0435 ppt
Miami-Dade Main System finished water (2025). Both bars run far past the 4 ppt line the EPA made enforceable in 2024 — PFOS about 8× over.

PFOS is about 8× the enforceable limit and roughly 1,600× the 2022 health advisory; PFOA is about 3× the limit and 3,000× the advisory. The health-based goal for both is zero — the EPA’s finding that no lifetime-safe level has been identified.

Sources: Miami-Dade County / City of Miami Beach 2025 Consumer Confidence Report · EPA NPDWR final rule (2024) · EPA Lifetime Health Advisory (2022). ppt = parts per trillion.

What is PFAS — and why it builds up

PFAS (say “PEE-fass”) are a family of thousands of man-made chemicals that make things non-stick, waterproof and stain-proof — and they are the active ingredient in the firefighting foam sprayed at airports and fire-training sites for 50+ years. They are built on the carbon–fluorine bond, the strongest in chemistry, so they do not break down — not in soil, not in water, not in the human body. That is why they are called “forever chemicals.”

Once you drink them, they bind to the proteins in your blood and leave only slowly: the body takes years to clear even half of a single dose — about 5 years for PFOS, up to 8 for PFHxS. In a home drinking the water every day, new PFAS arrive faster than old PFAS leave, so the amount in the body climbs year after year; peer-reviewed pharmacokinetics indicate the level in the blood settles at roughly 100× the level in the water. That is why the EPA’s health goal is zero — it has found no dose that is safe.

Because it accumulates, PFAS matters most for the smallest and still-developing bodies: it crosses the placenta and passes into breast milk, and children take in far more water per pound of body weight than adults. Pregnant and nursing mothers, infants, and young children carry the most risk from the same water.

Long-term exposure is linked, in the EPA’s and independent scientific record, to kidney and testicular cancer, thyroid disease, ulcerative colitis, high cholesterol, and pregnancy-induced hypertension — the six “probable links” established by the 69,000-person C8 Health Project. Separately, peer-reviewed studies tie childhood exposure to a weakened vaccine response, to effects on brain and neurological development, and to lower birth weight. In 2023 the WHO’s cancer agency classified PFOA as a Group 1 human carcinogen, its highest category.

In Miami-Dade specifically, thyroid cancer is the 2nd-highest of Florida’s 67 counties and runs more than double the U.S. rate in the hardest-hit neighborhoods beside the airport — the same corridor where PFAS is highest. This is an association, not proof of cause; the map’s Health section lays out the evidence and the honest caveats.

The good news: removing PFAS is a solved problem, not a theoretical one — proven methods remove up to 99.9% of it, including anion (ion) exchange, reverse osmosis, and atmospheric water generation. Reverse osmosis and ion exchange already run at municipal scale in neighboring Hialeah and North Miami Beach, and the same fix works at home \u2014 a certified anion-exchange stage into reverse osmosis, or an atmospheric water generator into reverse osmosis. A carbon or pitcher/fridge filter is a false comfort — it misses the short-chain PFAS and fades as it loads, so it is a stage, never the whole answer; and boiling only concentrates PFAS. Boiling does not; it only concentrates it.

Sources: EPA final PFAS drinking-water rule & zero health goal (2024) · Olsen 2007 & Li 2018 (elimination half-lives) · C8 Science Panel probable-link findings (2012) · IARC Group 1 classification of PFOA (2023) · Grandjean 2012, JAMA (childhood vaccine response) · SCAN360 (U. Miami Sylvester / Florida Cancer Data System), age-adjusted 2016–20 (Miami-Dade thyroid). Every figure traces to a primary source.

Investigation Nº 1

Why is thyroid cancer elevated in Miami?

Of every chemical in Miami’s water, one has an address. PFAS disrupts the thyroid more directly than any other gland. And in Miami-Dade, thyroid cancer isn’t one hotspot you can explain away — it’s nearly the whole county, hottest right where the airport’s firefighting foam reaches the water.
Thyroid rate  low → high firefighting-foam in that city’s water ▲ Miami Int’l Airport
Biscayne Bayairport / fire-trainingcorridor · highest ratesAventura — 27 per 100k · 2.1× the U.S. rateBrownsville — 18 per 100k · 1.4× the U.S. rateCoral Gables — 21 per 100k · 1.6× the U.S. rateCoral Terrace — 31 per 100k · 2.4× the U.S. rateCountry Club — 26 per 100k · 2.0× the U.S. rateCountry Walk — 23 per 100k · 1.8× the U.S. rateCutler Bay — 20 per 100k · 1.5× the U.S. rateDoral — 28 per 100k · 2.2× the U.S. rateFountainebleau — 22 per 100k · 1.7× the U.S. rateGlenvar Heights — 27 per 100k · 2.1× the U.S. rateGolden Glades — 13 per 100k · 1.0× the U.S. rateHallandale Beach — 22 per 100k · 1.7× the U.S. rateHialeah — 23 per 100k · 1.8× the U.S. rateHialeah Gardens — 22 per 100k · 1.7× the U.S. rateHomestead — 23 per 100k · 1.8× the U.S. rateIves Estates — 19 per 100k · 1.4× the U.S. rateKendale Lakes — 25 per 100k · 1.9× the U.S. rateKendall — 23 per 100k · 1.8× the U.S. rateKendall West — 27 per 100k · 2.1× the U.S. rateKey Biscayne — 27 per 100k · 2.1× the U.S. rateLeisure City — 26 per 100k · 2.0× the U.S. rateMiami — 23 per 100k · 1.8× the U.S. rateMiami Beach — 22 per 100k · 1.7× the U.S. rateMiami Gardens — 18 per 100k · 1.4× the U.S. rateMiami Lakes — 28 per 100k · 2.2× the U.S. rateMiami Springs — 31 per 100k · 2.4× the U.S. rateMiramar — 24 per 100k · 1.9× the U.S. rateNorth Bay Village — 36 per 100k · 2.8× the U.S. rateNorth Miami — 16 per 100k · 1.3× the U.S. rateNorth Miami Beach — 20 per 100k · 1.6× the U.S. rateOjus — 15 per 100k · 1.2× the U.S. rateOlympia Heights — 27 per 100k · 2.1× the U.S. ratePalmetto Bay — 17 per 100k · 1.3× the U.S. ratePalmetto Estates — 23 per 100k · 1.8× the U.S. ratePinecrest — 27 per 100k · 2.1× the U.S. ratePrinceton — 30 per 100k · 2.3× the U.S. rateRichmond West — 21 per 100k · 1.6× the U.S. rateSouth Miami Heights — 23 per 100k · 1.8× the U.S. rateSunny Isles Beach — 21 per 100k · 1.7× the U.S. rateSunset — 25 per 100k · 1.9× the U.S. rateSweetwater — 28 per 100k · 2.2× the U.S. rateTamiami — 22 per 100k · 1.7× the U.S. rateThe Crossings — 28 per 100k · 2.1× the U.S. rateThe Hammocks — 24 per 100k · 1.9× the U.S. rateWestchester — 26 per 100k · 2.0× the U.S. rateWest Little River — 19 per 100k · 1.5× the U.S. rateWest Park — 19 per 100k · 1.5× the U.S. rateWestwood Lakes — 29 per 100k · 2.3× the U.S. rateMIANorth Bay Village 36tiny island · foam among the highest
Each dot is a Miami-Dade city, placed on the map and colored by its thyroid-cancer rate; blue rings show the firefighting-foam marker (6:2 FTS) measured in that city’s drinking water. The deepest reds cluster on the airport / fire-training corridor — the same belt where the foam marker in the water is highest. Hover any city for its rate. Source: Florida Cancer Data System / SCAN360 (age-adjusted 2016–20); EPA UCMR5 (6:2 FTS).
47 of 48
Miami-Dade cities above the U.S. thyroid-cancer rate
+83%
above the national rate, on average across the county (1.83×)
#2
of Florida’s 67 counties — and rising while the U.S. rate falls
Childhood is the one developmental window that cannot be repeated. Before a child is born, the thyroid runs their brain development. That is why this gland — and this water — matters most for the smallest bodies, long before anyone is ever diagnosed.

Why the thyroid, specifically

In the blood, PFAS rides transthyretin — the protein that carries thyroid hormone — and blocks the iodine pump the gland needs to make it. The everyday version, hypothyroidism, isn’t tracked anywhere in Florida, so cancer is the only mappable tip.

Why it isn’t just “more screening”

If this were wealthy neighborhoods getting more scans, it would concentrate there. It doesn’t. Income and insurance explain only about 22% of the spread, thyroid tracks none of the other cancers, and working-class corridor cities sit at the very top.

What we do and don’t claim. This is an association, not proof of cause — a city-level pattern, not a verdict on any person. Thyroid cancer is also the most over-diagnosed tumor nationally; the checks above are why that doesn’t explain Miami’s pattern. What is unarguable: the rate is genuinely elevated, rising while the nation’s falls, and it rises with the airport’s foam marker in the water (6:2 FTS; ρ ≈ 0.46, p ≈ 0.045).
See it on the live map ▸ ⇫ Share this
Sources: SCAN360 / Florida Cancer Data System (place-level, 2016–20) · NCI State Cancer Profiles (Miami-Dade #2 of 67, 18.1/100k) · van Gerwen 2023 (thyroid-cancer OR 1.56 per doubling of serum PFOS) · UM/Sylvester 2025 (PFAS proximity associated with thyroid cancer). Association, not causation.

The limit keeps falling

Every time the science hardens, the “safe” number drops. It has only ever moved one direction.
before 2016
none
unregulated — no federal limit at all
2016
70
ppt — EPA advisory, called “safe”
2024
4
ppt — enforceable federal limit
2024
0
health goal — no safe level exists

The enforceable limit fell from an informal 70 to 4 in eight years, and the health-based goal is zero. When the goalposts move only one way, it is because the evidence keeps getting worse — yet most household habits still run on the old math.

Sources: EPA Lifetime Health Advisory (2016, 2022) · EPA final NPDWR — MCL & MCLG (April 2024).

The contamination isn’t new — the “safe” line just fell toward it

Measured PFOS in Miami’s finished water (red) has sat in a narrow, high band for over a decade. The regulatory “safe” level (green) collapsed underneath it.
201320162019202220257040no federal limit“safe” = 70limit 4 (2024) → goal 0no public data 2016–22

The federal government first measured PFOS in Miami’s drinking water in 2013 — 43 to 58 ppt across the county’s systems (EPA UCMR3). A decade later it is 31 to 38 (utility reports, 2023–25). The water did not get dramatically worse. What changed is the definition of “acceptable”: from no limit at all, to a 70 ppt advisory (2016), to a 4 ppt enforceable limit and a health goal of zero (2024). The line dropped roughly 18-fold — toward a contamination that was already there. (No finished-water PFOS was publicly reported for 2016–2022; UCMR3 ended in 2015 and UCMR5 did not begin until 2023.)

The tell
In 2025 — the year PFOS measured 33 — WASD’s report replaced “a safe and dependable supply of drinking water” with “a high-quality and dependable supply.” The number did not fall. The word “safe” did. Read the County’s 2025 report ▸

  See the measured number for your own ZIP ▸

Sources: EPA UCMR3 Archival Data Finder (2013–15) · EPA UCMR5 Data Finder (2023–25) · Miami-Dade WASD Water Quality Reports 2023 (PFOS 38), 2024 (31), 2025 (33) · EPA Lifetime Health Advisories (2016; 2022) · EPA final NPDWR / MCLG (2024). UCMR3’s 40 ppt reporting floor undercounts the early values; CCR figures are the year’s highest distribution value.

Cumulative Biological Load

It’s not one glass of water

It’s every interaction with water, every day, for years.

The wrong question is “Is my drinking water filtered?” The right question is “What is my family’s total water exposure over the next 20 years — and how do I EFFICIENTLY reduce PFAS as close to 0.00 as possible?” Because PFAS stay in the body for years, small daily exposures across many ordinary moments add up to a rising cumulative body burden. The body does not distinguish the ounce you drink from the gallon you bathe in, breathe as steam, and absorb through skin.

Baby formulaInfant bathPoolJacuzziShoweringCookingIceCoffeeBrushing teethWashing produce
many daily water moments  ×  365 days  ×  years  =  a body burden that climbs

Every home has more than one water pathway — ranked here by the weight of evidence:

Drinking & cooking strongest evidence
The dominant, best-characterized route. Boiling does not help — it concentrates PFAS (pasta water, broth, rice, and infant formula made from the tap).
Skin, shower, bath, pool, jacuzzi emerging
It was long assumed PFAS did not cross the skin barrier. A 2024 University of Birmingham study (Ragnarsdóttir et al., Environment International) found 15 of 17 PFAS absorbed through lab-grade skin; short-chain PFAS absorb more. Emerging work also suggests PFAS can harbor in the skin and dose the body over time as a slow drip. The infant bath — and the pool and jacuzzi — mean warm water and long skin contact; a small child has thinner skin, more surface per pound, and hands going to the mouth, making these the largest pediatric exposure surfaces. The EPA’s health goal (MCLG) is 0.00 — no level of PFAS is considered safe.

The bath you put your child in is the same water you would not put in your own glass. Childhood is the one developmental window that cannot be repeated: a mother’s PFAS burden at conception becomes the infant’s starting burden, and the systems being built — brain, immune, hormones, bone — calibrate during exactly the years exposure is highest.

Sources: Ragnarsdóttir et al. 2024 (dermal absorption) · peer-reviewed shower-aerosol PM measurements · EPA (children more exposed per pound of body weight) · HOME Study (pediatric bone density) · Rigano Water Institute whitepaper (full citations). Association and cumulative-exposure science; not a prediction for any individual.

How your water gets to you
Source to tap, in four steps — every one from the public record.
Miami International Airport
Firefighting foam (AFFF) has been used here since the 1970s. It doesn’t break down — it soaked into the ground.
Miami Springs wellfield
The wells that supply the county draw from the Biscayne Aquifer, just 2–5 ft down — right beside the foam.
Hialeah treatment plant
The plant removes no PFAS. The foam marker 6:2 FTS leaves here at 190 ppt — with no legal limit at all.
Your tap
It arrives unchanged — PFOS about 8× the federal limit, and most of the PFAS unregulated. The EPA’s safe level is zero.
Sources: Florida DEP · USGS FS 2019-3056 · EPA UCMR5 · Miami-Dade 2025 Water Quality Report.  ·  ▶ watch it animate on the map

Two cities, two ways to get water

A viral map recently called New York’s water system “genius.” It is — and the comparison explains Miami exactly.
NEW YORK — distance & protection protected watershed ≈ 125 miles · by gravity the tap So clean at the source the EPA lets NYC run one of the largest unfiltered water systems on earth. MIAMI — shallow & exposed Biscayne Aquifer · top just 2–5 ft down, highly permeable ✈ MIA · firefighting foam, 50 yrs plant — removes no PFAS Pumped from a shallow aquifer beside the airport — and the treatment plants remove none of the PFAS.

New York moves roughly a billion gallons a day to nearly 10 million people, almost entirely by gravity, from three protected watersheds up to 125 miles away — through tunnels like the 85-mile Delaware Aqueduct, the world’s longest. Because the land around the source is kept wild, the water arrives clean enough that the EPA permits it to run unfiltered. The design puts distance and protection between people and their water.

Miami-Dade’s design is the opposite. Its drinking water is pumped from the Biscayne Aquifer — an unconfined limestone formation whose top sits just 2 to 5 feet below the surface, so permeable that a spill at ground level reaches the water table quickly. Some of the wellfields sit right beside Miami International Airport, where firefighting foam was used for decades — and the treatment plants do not remove PFAS. There is little distance, and little protection, between the surface and the glass.

Sources: NYC DEP (Water Supply; Filtration Avoidance Determination) · National Academies review of the NYC Watershed Protection Program · USGS Fact Sheet 2019-3056 & Ground Water Atlas HA 730-G (Biscayne Aquifer) · Miami-Dade Wellfield Protection / Aquifer Recharge Element (2026). Inspired by “New York’s Genius Water Supply System,” Epic Maps.

Your child’s school drinks the same water

A school has no wells and no filter of its own. Every fountain, every cafeteria sink, every batch of ice is the same system water as the homes around it — from the same plant, off the same wellfield.

Schools on the airport side are fed by the Hialeah / Preston plants, whose wells sit beside 50 years of firefighting foam — the foam marker 6:2 FTS runs 190 ppt in that finished water. Schools fed by Alexander Orr, farthest from the airport, read 0. Same county, two different glasses.

Find your school and the report traces the whole chain — school → system → plant → wellfield → airport-side? → the finished-water PFOS — using the government’s own published numbers, nothing modeled.

or browse every school on the map ▸  · 

Sources: Miami-Dade School Site geometry (County GIS) · EPA UCMR5 per-plant finished water · Miami-Dade / utility Consumer Confidence Reports. The plant number is finished water, not this school’s specific fountain.

Straight answers, rated by the evidence

Every answer is evidence → answer → confidence. When the science changes, these change.
QuestionAnswerConfidence
Does PFAS build up in the body over years?Yes★★★★★
Is Miami’s finished water above the federal PFAS limit?Yes — about 8×★★★★★
How far over the 2022 EPA health advisory is that water?>1,500× over★★★★★
Does PFAS cross the placenta and enter breast milk?Yes★★★★★
Is there a known safe level of PFOA or PFOS?No (goal is 0)★★★★★
Does boiling remove PFAS?No — it concentrates it★★★★★
Can PFAS be absorbed through skin?Yes — lab models (15 of 17)★★☆☆☆
Does filtering only the drinking tap address every route?No★★★★☆
So should every household install whole-home treatment?Ideally yes★★★☆☆
Does a carbon or pitcher filter fully remove PFAS?No — misses short-chain, fades as it loads★★★★★
Which setup removes the most PFAS?AWG → RO, then anion exchange → RO★★★★☆
Is bottled water a reliable fix?No — unregulated, varies by brand★★★☆☆
Does routine showering materially raise body burden?Unknown — emerging★★☆☆☆
Is it possible to reduce PFAS already in the body?Yes — emerging (see Protocols)★★★★☆
Does a sauna “sweat out” PFAS?No — negligible★★★★★

Confidence reflects the weight of primary evidence, not opinion — ★★★★★ settled, ★★☆☆☆ still emerging. Every figure traces to the sections above. Treatment options are covered separately, evidence-rated and without brand recommendations.

How we know it’s the airport and firefighting foam

This whole report is built from the government’s own records. Here is the chain — and the honest limits of it.
The chemical fingerprint

6:2 FTS is a marker of aqueous film-forming foam (AFFF) — the firefighting foam sprayed at airports and fire-training sites since the 1970s. It does not occur in nature, so where it turns up in drinking water, foam put it there. In the EPA’s own federal monitoring, 6:2 FTS leaves the airport-side Hialeah plant at 190 ppt — the highest reading in the county — exactly where Miami International and the County’s own fire-training academy have used AFFF for decades. The County’s own groundwater monitoring at that academy measured PFOS in the tens of thousands of ppt (groundwater at the source — not drinking water). The chemistry, the location, and the decades of foam use all line up: the source is AFFF.

They have known since 2013

This is not new. The first nationwide federal PFAS survey (EPA UCMR3) measured it in South Florida’s finished drinking water more than a decade ago — and every system that reported was already 10 to 14 times over the 4 ppt limit the EPA would not make enforceable until 2024:

SampledSystemPFOS measuredvs. today’s 4 ppt limit
2014City of Miami Beach58 ppt14× over
2013City of North Miami50 ppt12× over
2013–15FKAA — Florida Keys49 ppt12× over
2013–15City of Lauderhill49 ppt12× over
2013Miami Int’l Airport — county water47 ppt11× over
2013–15City of Miramar47 ppt11× over
2015Miami-Dade Main System43 ppt10× over
The County found it — and kept pumping
89 wells sampled  →  6 over the limit  →  3 taken out of service  →  3 kept pumping

In January 2020 the County reported 6 of 89 wells over the health advisory and took only three out of service; the other three kept pumping. Its own director later put it at 70 of 95 wells with detectable PFAS. The Miami Springs wells it shut had been feeding the tap at 124, 182 and 184 ppt. Its own official confirmed the treatment plants “do not remove PFAS,” and the utility says it manages which wells it runs “to maximize output from more pristine sources.” The delivered number therefore measures the blending, not the source.

The same County wears three hats
Owns the sourceMiami International Airport, where the foam has been used since the 1970s.
Sells the waterMiami-Dade WASD — which called the finished water “excellent” and “safe,” then quietly dropped “safe.” The City of Miami Beach still calls its water “excellent — not just safe.”
Is suing over itA plaintiff in the federal AFFF litigation (MDL 2873), seeking about $199M for the same PFAS contamination.
What we will not claim
PFAS in Miami is not only an airport story. The peer-reviewed record also attributes PFAS to wastewater, landfills and industry, and the physically separate South Dade system — 25 miles away, near Homestead’s own airfield — runs high too. AFFF at Miami International is a documented, dominant hotspot; it is not the only source. We would rather tell you that than have you hear it from the other side. It is even in the rain, at single-digit levels — a real but minor route we publish precisely so no one can wave the tap numbers away as “just background.”

Sources: EPA UCMR5 (6:2 FTS per plant) · Florida DEP fire-training assessments (Fire Academy groundwater) · EPA UCMR3 Archival Data Finder 2013–15 (MIA PWS FL4134513, PFOS 47, 9/26/2013) · EPA final NPDWR 2024 (PFOS MCL 4 ppt — the multiple-over basis) · Miami-Dade DERM (2026-01-08) · WASD statements (2020-01-23; K. Lynskey; D. Yoder, Miami New Times) · In re AFFF Products Liability Litigation, MDL No. 2873 · FIU/Quinete (rainwater). Government and peer-reviewed records only; the well-by-well table remains an unreleased public record.

When another utility found PFAS, it warned people

A compliant water system in Wisconsin shows the honest alternative — and a state health department recommends exactly the fix.

In a formal Drinking Water Advisory, Walworth Waterworks in Wisconsin reported PFAS in one of its wells above health-based standards. Its state health department’s response was to tell residents to reduce their exposure: the Wisconsin Department of Health Services “recommends people limit their intake of PFAS compounds,” and advised limiting consumption of the utility’s water and using a certified anion-exchange → reverse-osmosis filter (NSF/ANSI 58). “Boiling water does not remove PFAS.”

Wisconsin Dept. of Health Services · Drinking Water Advisory
Public Water System
Walworth Waterworks — Walworth, Wisconsin

PFAS were detected in a municipal well above health-based groundwater standards. The Department of Health Services “recommends people limit their intake of PFAS compounds.”

Residents are advised to limit consumption of the water and to use a certified anion-exchange → reverse-osmosis filter (NSF/ANSI 58). “Boiling water does not remove PFAS.”

Compliance status, stated in the same advisory: the system “is not in violation of any federal or state drinking water standards or regulations.”
The part that matters

The same advisory states the utility “is not in violation of any federal or state drinking water standards or regulations.” Fully compliant — and it still warned its customers, in writing, to drink less of the water and to filter it.

Miami-Dade’s finished water runs about 8× the federal PFOS limit. It, too, is compliant — on the 2031 compliance timeline. Its 2025 report calls the water “high-quality” and communicates its “excellence.” Two utilities, the same federal law, opposite messages. You decide which one is protecting your family.

One honest note: the Wisconsin advisory reflects the cautious agency position that skin contact is low-risk. Newer peer-reviewed work (Birmingham, 2024) finds many PFAS do absorb through skin — the science is still moving. Both agree drinking is the dominant route, and both point to the same certified filters.

Source: Walworth Waterworks / Wisconsin Department of Health Services Drinking Water Advisory; sample results via Wisconsin DNR ▸. Miami-Dade wording: Miami-Dade 2025 Water Quality Report.

What to do — three steps, no products

You don’t need to panic, and you don’t need permission. The record is enough to act on.
1
Know your number. Look up your ZIP and your child’s school — the exact finished-water reading and which plant and wellfield feed it. Check your ZIP ▸
2
Know the standard that works. Independent certification — NSF/ANSI 58 (anion exchange into reverse osmosis, with a named PFOA/PFOS claim) — is what actually reduces PFAS exposure as close to 0.00 as possible; see also atmospheric water generation. Boiling concentrates PFAS. Match the certification to the pathways that matter for your household, not a brand.
3
Move it upstream. The fastest change is institutional. Bring this — with its sources — to your pediatrician, HOA board, or school. One installation protects hundreds of children; one informed physician reaches thousands of families.

We do not sell filters.

The next chapter of the oldest public-health work

Water has always been the foundation of health. This is a continuation of that work — not a scare.

In 1842, the lawyer and reformer Edwin Chadwick showed that clean water is the foundation of a healthy population, and helped launch the sanitary revolution in Britain: engineered sewers, filtered municipal water, and the Public Health Act of 1848.

The payoff was the largest in the history of medicine. Readers of the British Medical Journal (BMJ) later voted that “sanitary revolution” — clean water and sewage disposal — the greatest medical advance since 1840, ahead of antibiotics and vaccines. Clean water alone drove roughly half of the U.S. mortality decline in the early 20th century and helped lift life expectancy from 47 to 63 years (Cutler & Miller, 2005).

That work removed what people could see and smell — the pathogens behind cholera and typhoid. In Miami-Dade, the water is microbially clear; that first battle was largely won. What it carries now is what the Victorians never faced: invisible, man-made industrial chemicals that do not break down and slowly accumulate. This is the next chapter of the same story — and the same principle holds: it is wiser, and historically cheaper, to protect the water at the source than to treat the consequences downstream.

Sources: Chadwick, 1842 (UK Parliament, Living Heritage) · Cutler & Miller, “The Role of Public Health Improvements in Health Advances,” Demography (2005) · BMJ readers’ poll (2007).

The evidence, with its sources

Every claim on this site traces to a primary source. Where a figure rests on our whitepaper’s synthesis rather than a single indexed study — or where a link is our inference — we mark it ⚑ so you can verify before you rely on it.
Persistence & how it builds up
PFAS are built on the carbon–fluorine bond, among the strongest in organic chemistry (~485 kJ/mol) — it resists water, oxygen, sunlight, microbes and human metabolism, so they never break down.
General chemistry; Rigano Water Institute whitepaper
PFAS leave the body slowly: it takes years to clear even half a dose — PFOA ~2.7–3.5 yr, PFOS ~4.8–5.4 yr, PFHxS ~5–8 yr.
Serum half-life literature (attach primary citation) ⚑ primary citation / inference pending verification
Drinking low-level PFAS water for years can push blood levels toward roughly 100× the water concentration (enterohepatic recirculation keeps returning it).
Peer-reviewed pharmacokinetics, per whitepaper ⚑ primary citation / inference pending verification
Regulatory standards & the zero goal
First federally enforceable limit for PFOA and PFOS: 4 parts per trillion, finalized April 10, 2024.
U.S. EPA, PFAS National Primary Drinking Water Regulation (2024)
The health-based goal (MCLG) for PFOA and PFOS is zero — no exposure has been shown to be without risk. The 4 ppt limit is a feasibility compromise, not a safety threshold.
U.S. EPA NPDWR (2024)
EPA’s 2022 lifetime health advisories put the ‘no appreciable risk’ level at 0.004 ppt (PFOA) and 0.02 ppt (PFOS).
U.S. EPA, Lifetime Health Advisories, June 21, 2022
Utility compliance with the limits was extended to 2031, leaving households exposed in the interim.
U.S. EPA announcement, May 14, 2025
Thyroid
PFOS disrupts the thyroid: it knocks thyroid hormone (T4) off its carrier protein (transthyretin) and blocks the iodine pump (sodium-iodide symporter).
Weiss 2009; Ren 2016 (mechanistic)
Each doubling of blood PFOS raised the odds of thyroid cancer ~56% (OR 1.56), rising to 2.67 when measured a year before diagnosis.
van Gerwen et al. 2023, eBioMedicine 97:104831
Across Florida census tracts, living near a PFAS source independently predicts higher papillary thyroid cancer; Miami-Dade is among the most PFAS-dense counties.
Wild et al. 2025, IJERPH 22:1290 (PMID 40869875)
Miami-Dade’s thyroid-cancer rate (~18/100k) is ~40% above the U.S. and the 2nd-highest of Florida’s 67 counties, rising while the national rate falls.
NCI State Cancer Profiles (age-adjusted)
Florida’s primary young-adult thyroid cluster spans Miami-Dade + Broward + Palm Beach (RR 1.26, p<0.001).
Amin & Burns 2014, BioMed Research Intl (PMID 24868551) ⚑ primary citation / inference pending verification
Kidney & other cancers
The C8 Science Panel (69,000 people) found six probable links to PFOA: kidney cancer, testicular cancer, ulcerative colitis, thyroid disease, pregnancy-induced hypertension, and high cholesterol.
C8 Science Panel, 2005–2013
Ulcerative colitis was 2.86× more common in the highest vs lowest PFOA-exposure group.
Steenland et al. (C8), PMC3734500
In November 2023 the WHO’s cancer agency (IARC) classified PFOA as carcinogenic to humans — Group 1, its highest category.
IARC Monograph 135, 2023
Miami-Dade kidney cancer is rising while the U.S. rate falls (the signal is the divergent trend, not the level).
NCI State Cancer Profiles; FLHealthCHARTS
Pregnancy, infancy & childhood
PFAS cross the placenta efficiently (transfer often >50%), so a mother’s burden at conception becomes the baby’s starting burden; breast milk is a second route.
Published birth cohorts, per whitepaper ⚑ primary citation / inference pending verification
Higher PFOA raised the odds of pregnancy-induced high blood pressure / preeclampsia ~27% per log-unit (OR ~1.27).
Darrow et al. 2013 (PMID 23739657)
A second-trimester pregnancy-loss study linked PFOA and PFHpS to miscarriage.
Liew et al. 2020, Environ Health Perspect 128:047007
Higher maternal PFAS is associated with modestly lower infant birth weight (~ −10.5 g).
Steenland 2018
EPA states children are more sensitive to PFAS — still developing, and exposed to more per pound of body weight than adults.
U.S. EPA, PFAS health page (2026)
Prenatal PFAS is associated in prospective cohorts with slightly lower child IQ, language delay, and higher odds of ADHD/autism.
European & Asian birth cohorts, per whitepaper ⚑ primary citation / inference pending verification
Immune & skeletal
Each doubling of a child’s blood PFAS was linked to ~49% lower vaccine antibody levels — the most sensitive endpoint EPA used to set the 2024 limits.
Grandjean et al. 2012, JAMA
In children followed to age 12 (HOME Study), higher PFOA and cumulative PFAS were tied to lower bone-mineral density at the wrist.
HOME Study pediatric cohort (attach citation) ⚑ primary citation / inference pending verification
In women, higher PFOA and PFHxS were associated with higher odds of osteoporosis (OR 1.84 / 1.64).
Khalil et al. 2016, Environ Health Perspect (PMID 26058082)
Exposure beyond drinking
In a 3D-human-skin study, 15 of 17 PFAS were absorbed through skin; for PFOA, 13.5% of the dose entered the blood and 38% lodged in the skin; short-chains absorbed up to 4× faster.
Ragnarsdóttir, Abou-Elwafa Abdallah & Harrad 2024, Environment International
Hot showers generate respirable PM10 aerosols (300–14,000 µg/m³ within five minutes), giving PFAS an inhalation route.
Aerosol PM literature, per whitepaper ⚑ primary citation / inference pending verification
Boiling and cooking do not remove PFAS — evaporating water down (pasta, broth, rice, formula) concentrates what remains.
Physical chemistry; whitepaper ⚑ primary citation / inference pending verification
Miami: the source & the local data
The firefighting-foam marker 6:2 FTS runs 128.9–190 ppt at the airport-side Hialeah plant — the county’s highest — and it has no federal limit.
U.S. EPA UCMR5, per-plant entry points
Miami’s finished water was reported at PFOS 38 / PFOA 30 ppt (~9.5× / 7.5× the limit) in the same reports that call it ‘excellent’ and ‘safe.’
City of Miami Beach AWQR (2023); Miami-Dade WASD CCR
A neighborhood tap study found mean total PFAS of 226 ppt in downtown ZIP 33128 and mean PFOS above 4 ppt in 16 of 16 Miami-Dade ZIPs.
Cuchimaque Lugo, Guerra de Navarro & Quinete 2026, Environ Research 294:123822
The single highest South Florida tap total — 242 ppt — was at Grapeland Heights, next to Miami International Airport.
Vega Millán & Quinete 2021, Sci Total Environ
6:2 FTS — an airport-foam fingerprint — is the dominant PFAS in the Miami River, which flows past MIA to Biscayne Bay.
Ogunbiyi, Massenat & Quinete 2024, Sci Total Environ
Florida DEP confirmed PFAS in groundwater above EPA standards at four Miami-area fire-training sites — but has not assessed MIA itself, a documented gap.
Florida DEP Preliminary Site Assessments (from 2019)
Wells upgradient of the airport read ~1–2 ppt PFOA/PFOS; the wellfields at and downgradient of MIA that supply the county read 30–38 — about 10× higher.
Miami-Dade DERM sampling; whitepaper
Miami-Dade said 6 of 89 wells exceeded advisory levels; it took 3 out of service and kept 3 pumping, and its own official confirmed the plants ‘do not remove PFAS.’
WASD (2020-01-23; Yoder); DERM (2026-01-08)
Miami-Dade County owns the airport (the source), owns the utility that sells the water, and is a plaintiff in the federal AFFF litigation seeking ~$199M for PFAS contamination.
In re AFFF Products Liability Litigation, MDL No. 2873

This library is a living document; entries are added and corrected as the science moves. Figures flagged ⚑ are directionally supported but await a specific indexed citation or are labeled inferences (e.g., the Amin & Burns cluster paper names radiation and iodine, not PFAS — the airport/AFFF overlay is our inference).

Rigano Water Institute Investigations My Water The Map Evidence Protocols About