Your water quality report, rewritten.
2026 edition
U.S. EPA data
10,433 utility reports
Your utility has to send you a water quality report every year, and most go straight into the recycling. Enter your ZIP code to see what EPA’s own records show is in your tap water, how each result compares with the legal limit and the health goal, and which certified filter handles it.
On a private well? No utility reports on your water, so the first step is a test. How to test well water
Philadelphia Water Department
PWSID PA1510001 · Serves 1.6 million people · Philadelphia, PA · Surface water
PFOA
Comes from the source
8.1ppt
Highest of 12 samples; found in eight
Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.
EPA UCMR 5, samples taken from Jan. 8, 2024 to Oct. 7, 2024. Each blue tick is one sample where it was found.
What handles it
- NSF/ANSI 53 with the claim “PFOA Reduction”
- NSF/ANSI 58 with the claim “Perfluorooctanoic Acid (PFOA)”
Every result, on two yardsticks.
A utility report prints one number per contaminant and a column of acronyms. TapBuff measures each result against both lines EPA sets, and marks the ones worth your attention.
- Health goal
- The level below which EPA expects no risk to health, with a margin of safety. Not enforceable. EPA calls it the MCLG. For PFOA, PFOS and lead it is zero.
- Legal limit
- The most a utility may deliver, set as close to the goal as treatment and cost allow. Enforceable. EPA calls it the MCL. For lead and copper there is an action level instead.
- Highlighted
- Above the health goal in at least one result. Worth reading about, not a reason to panic.
- Circled
- Above the legal limit in at least one sample. Compliance is judged on averages over time, so this is not by itself a violation.
Where it gets in decides what fixes it.
Water picks things up at three points between the source and your glass. A report row tells you what; this tells you where, which decides the kind of filter that can help.
1At the source
Rivers, lakes and aquifers carry these into the treatment plant. Whether they reach you depends on what the plant removes.
What helps: A filter certified for the specific contaminant, at the tap or for the whole house.
2In treatment
Chlorine or chloramine keeps water safe on its way to you. Byproducts form when the disinfectant meets organic matter.
What helps: Carbon handles taste and odor. Byproducts need a health-effects claim, not just a taste claim.
3In your pipes
Lead and copper usually come from service lines, solder and fixtures. The utility’s plant never sees them.
What helps: Only a filter at the tap catches what your own plumbing adds after a whole-house unit.
What EPA found when it tested 9,949 utilities.
EPA’s fifth Unregulated Contaminant Monitoring Rule, UCMR 5, tested nearly every utility serving more than 3,300 people for 29 PFAS and lithium. PFAS turned up in 3,506 of them, which report serving 153 million people. At 1,667, at least one sample of PFOA or PFOS was above the new 4.0 ppt legal limit.
| Contaminant | Federal line | Utilities where found | Highest sample | People they serve |
|---|---|---|---|---|
| PFOA | 4.0 ppt limit | 1,274 | 235 ppt | 62 million |
| PFOS | 4.0 ppt limit | 1,320 | 490 ppt | 68 million |
| PFHxS | 10 ppt limit | 1,015 | 153 ppt | 52 million |
| PFNA | 10 ppt limit | 78 | 99.8 ppt | 8.9 million |
| HFPO-DA (GenX) | 10 ppt limit | 47 | 170 ppt | 1.8 million |
| PFBS | 2,000 ppt benchmark | 1,672 | 290 ppt | 86 million |
| Lithium | 10 ppb benchmark | 3,621 | 960 ppb | 108 million |
Source: EPA UCMR 5 occurrence data, file of Aug. 27, 2026. “Found” means at or above EPA’s minimum reporting level in at least one sample. People served is what each utility reports to EPA; where one utility sells water to another, the same people can be counted twice.
The number on the box, decoded.
Every standard, in fullA filter certified to a standard is only certified for the specific claims on its listing. Two filters can both say “NSF/ANSI 53” and remove different things.
42
Taste, odor and appearance
A product certified to NSF/ANSI 42 was tested to reduce things that affect taste, smell or look, not health. It is certified only for the specific claims on its listing.
Often misread
Many sites say a filter certified to NSF/ANSI 42 removes lead. It does not. Every 42 claim is aesthetic, and lead reduction is a separate health claim under NSF/ANSI 53 or 58.
53
Health-related contaminants
Covers filters tested to reduce contaminants with health effects, such as lead, cysts, VOCs and PFOA/PFOS. A certified product holds only the claims on its listing, not every claim in the standard.
Often misread
Reading "certified to NSF/ANSI 53" as "removes everything in 53." Certification is per claim. A filter certified to 53 only for cyst reduction has not been shown to reduce lead.
58
Reverse osmosis systems
Covers point-of-use reverse osmosis (RO) systems. Every certified system must reduce total dissolved solids (TDS). Other claims, like lead or nitrate, are optional and listed per product.
Often misread
Assuming every RO system removes everything RO can remove. Only TDS reduction is required. Lead, nitrate, arsenic and PFAS are separate claims that a given system may or may not hold.
401
Emerging contaminants
Covers filters tested to reduce trace contaminants that EPA does not regulate, such as some drugs, pesticides, BPA and microplastics. Each compound is its own claim.
Often misread
Saying a 401 filter "removes pharmaceuticals" in general. Each claim covers one named compound, and a product may hold only some of them.
P473
Retired PFOA/PFOS protocol
A former NSF test protocol for PFOA and PFOS reduction. NSF moved its claims into NSF/ANSI 53 and 58 and removed all products and references to P473.
Often misread
Calling it "NSF/ANSI 473" and treating it as a live PFAS standard. NSF calls it Protocol P473, and its claims were folded into NSF/ANSI 53 and 58.
Count the whole cost.
The price on the box is the down payment. Cartridges are the rest, and they decide which filter is cheap.
Run your own numbersFive-year statement
Household of 3 · 3 gal a day · 5,479 gal total
| Type | Lowest five-year cost | Total | Per gallon |
|---|---|---|---|
| Pitcher | Brita Tahoe Pitcher with Elite Filter (OB60, OB06)$42 up front, $900 in cartridges; highest in catalog $7,334 | $942 | 17¢ |
| Faucet mount | Brita Elite Water Filter Faucet System (SAFF-100/FF-100)$32 up front, $971 in cartridges | $1,004 | 18¢ |
| Under-sink carbon | Aquasana Claryum Direct Connect (AQ-MF-1)$250 up front, $828 in cartridges; highest in catalog $1,215 | $1,078 | 20¢ |
| Under-sink reverse osmosis | APEC Essence ROES-50$231 up front, $335 in cartridges; highest in catalog $1,149 | $566 | 10¢ |
| Countertop reverse osmosis | AquaTru Classic (AT2000)$475 up front, $869 in cartridges | $1,344 | 25¢ |
Makers’ own list prices, checked Oct. 4, 2026. Cartridges replaced at the maker’s gallon or month rating, whichever comes first. Assumes 1 gallon of drinking and cooking water per person per day; change it in the calculator.
Open your own report.
35,489 ZIP codes, matched to the utilities that serve them.