Tap water report · updated November 2026
Baltimore tap water: moderately hard water, no PFOA or PFOS found
What’s in the water Baltimore City Department of Public Works delivers to 1.6 million people, from national testing by the U.S. Environmental Protection Agency (EPA) and the utility’s own report.
Short answer
Baltimore tap water is moderately hard: about 5.5 grains per gallon (94 milligrams per liter (mg/L)), depending on which treatment plant serves your neighborhood (78 to 110 mg/L), according to published water quality data from Baltimore City Department of Public Works (2021, the most recent figures we found). The U.S. Environmental Protection Agency’s (EPA’s) 2024–25 testing found no PFOA or PFOS (two PFAS “forever chemicals”) at or above its 4 parts per trillion (ppt) limit. The system had 3 health-based violations in the five years through September 2026.
Sources: Baltimore City Department of Public Works 2021 data, EPA UCMR 5, EPA SDWIS 2026Q3 · Sources and method
None found
every sample under 4 ppt
Under EPA’s 4 ppt limit
EPA UCMR 5, sampled 2024–25
How Baltimore compares with the 40 systems we track
Hardness
10th softest
of 34 systems
PFOA / PFOS
Not detected
in any EPA sample
Size
9th 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 Baltimore 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, 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 5.5 gpg, Baltimore water is in the middle of the scale, the 10th-softest of the 34 systems we track. Some homes notice spots; many don’t.
What to do: A softener is optional. If spots bother you, a small one does the job.
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)
Nothing to doPFAS 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: EPA’s 2024–25 testing found no PFOA or PFOS in Baltimore’s water at or above 4 ppt, the lowest level labs can reliably measure. 29 of the 40 systems we track can say the same; 11 had a sample over the limit.
What to do: Nothing needed by EPA’s standard. If you want PFAS lower still, the same certified filters apply.
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: Baltimore uses free chlorine. It’s the one that can give tap water a slight pool smell, and it’s easy to filter.
What to do: For taste, any carbon filter certified to NSF/ANSI 42 for chlorine works.
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
Worth knowingA 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: Baltimore’s system had 3 in the five years through September 2026. 36 of the 40 systems we track had none.
What to do: Utilities must notify customers when a violation happens. The utility’s annual water quality report explains what happened and what was fixed.
Learn more →How Baltimore 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.
Baltimore: none at or above 4 ppt. Like 28 other systems we track, EPA’s testing found no PFOA or PFOS there. These 11 did:
- 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 Baltimore
02 · The full results
Every PFAS result EPA recorded
EPA’s national testing (sampled 2024 to 2025) found no PFOA or PFOS at or above 4 ppt in any of 12 samples, which puts Baltimore under EPA’s limit for both.
Results from EPA’s national testing program (UCMR 5) for Baltimore City Department of Public Works, 3 sampling points, August 2024 to May 2025. Concentrations in parts per trillion (ppt).
| Chemical | Samples | Detected | Highest | EPA limit |
|---|---|---|---|---|
| PFOA (perfluorooctanoic acid) | 12 | 0 | none | 4 |
| PFOS (perfluorooctane sulfonic acid) | 12 | 0 | none | 4 |
| PFHxS | 12 | 0 | none | 10 |
| PFNA | 12 | 0 | none | 10 |
| HFPO-DA (GenX) | 12 | 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
Baltimore’s water comes from the Liberty, Loch Raven and Prettyboy reservoirs, and water from the Susquehanna River is used only during severe drought.
Baltimore City Department of Public Works serves about 1.6 million people directly, and 7 other water systems buy water from it, serving about 290,654 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.
DPW serves about 1.8 million customers across the Baltimore region from the Ashburton and Montebello treatment plants.
EPA’s federal database shows 3 health-based violations in the five years through September 2026. The system went over EPA’s limit for TTHM (total trihalomethanes), a group of disinfection byproducts, in January 2026 and April 2026 and went over a limit under EPA’s bacteria rule (the Revised Total Coliform Rule) in September 2022, since resolved.
Largest systems that buy from Baltimore City Department of Public Works
- Howard County D.p.w. Distribution286,158
- Johns Hopkins University2,058
- Stella Maris873
- Keswick Multi-care Center575
- Metropolitan of Baltimore414
- Elkridge Estates of Roland Park414
- The Neighborhoods at St. Elizabeth162
From EPA’s federal drinking water database (SDWIS), 2026Q3: community systems with an active connection buying from MD0300002. Population served.
ZIP codes Baltimore City Department of Public Works reports serving (78)
21013 · 21027 · 21030 · 21031 · 21043 · 21051 · 21052 · 21065 · 21071 · 21082 · 21085 · 21087 · 21092 · 21104 · 21117 · 21128 · 21131 · 21133 · 21136 · 21139 · 21156 · 21162 · 21163 · 21201 · 21202 · 21203 · 21204 · 21205 · 21206 · 21207 · 21208 · 21209 · 21210 · 21211 · 21212 · 21213 · 21214 · 21215 · 21216 · 21217 · 21218 · 21219 · 21220 · 21221 · 21222 · 21223 · 21224 · 21227 · 21228 · 21229 · 21230 · 21231 · 21233 · 21234 · 21235 · 21236 · 21237 · 21239 · 21240 · 21241 · 21244 · 21250 · 21251 · 21263 · 21264 · 21270 · 21273 · 21275 · 21278 · 21279 · 21281 · 21282 · 21286 · 21287 · 21289 · 21290 · 21297 · 21298
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
Baltimore water questions
Is Baltimore 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, Baltimore’s water system had 3 health-based violations in the five years through September 2026. EPA’s 2024–25 testing found no PFOA or PFOS (two PFAS “forever chemicals”) samples above its 4 parts per trillion (ppt) limit.
Is Baltimore tap water hard?
Baltimore tap water is moderately hard: about 5.5 grains per gallon (94 milligrams per liter (mg/L)), depending on which treatment plant serves your neighborhood (78 to 110 mg/L), according to published water quality data from Baltimore City Department of Public Works (2021, the most recent figures we found).
Does Baltimore tap water have PFAS?
The U.S. Environmental Protection Agency’s (EPA’s) national testing (sampled 2024 to 2025) found no PFOA or PFOS (two PFAS “forever chemicals”) at or above 4 parts per trillion (ppt) in any of 12 samples, which puts Baltimore under EPA’s limit for both.
Does Baltimore use chlorine or chloramine?
Free chlorine. Baltimore City Department of Public Works (DPW) says treatment plant staff disinfect the water by adding sodium hypochlorite or chlorine, and its 2025 table lists chlorine as the disinfectant at both the Ashburton and Montebello plants.
Has Baltimore’s water system had violations?
The U.S. Environmental Protection Agency’s (EPA’s) federal database shows 3 health-based violations in the five years through September 2026. The system went over EPA’s limit for TTHM (total trihalomethanes), a group of disinfection byproducts, in January 2026 and April 2026 and went over a limit under EPA’s bacteria rule (the Revised Total Coliform Rule) in September 2022, since resolved.
Nearest cities we cover
Sources
- 01Baltimore City Department of Public Works, 2021 water quality data (hardness), read 2026-11-04
- 02Baltimore City Department of Public Works (source water)
- 03Baltimore City Department of Public Works (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 MD0300002 · Baltimore City Department of Public Works