Water Quality Report · Updated May 12, 2026
MWRA
MWRA delivers tap water graded D (60/100) by TapWaterSafety.org. The utility serves approximately 2,660,000 residents in BOSTON, Massachusetts using surface water. The most significant water quality concerns are: PFAS contamination; Haloacetic acids (HAA5) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; Dichloroacetic acid significantly above health guideline. For questions, the utility can be reached at 6172426000.
Is BOSTON tap water safe to drink?
MWRA delivers tap water that earns a grade of D (60/100) from TapWaterSafety.org — a below-average rating, with multiple concerns including pfas contamination.
The utility serves 2,660,000 residents in BOSTON, drawing from surface water.
Public testing data identifies 10 contaminants in this water above EWG's health-based guidelines, including: Haloacetic acids (HAA5), Total trihalomethanes (TTHMs), Dichloroacetic acid, Bromodichloromethane, Chloroform, Trichloroacetic acid, Perfluorooctanoic acid (PFOA), Dibromochloromethane, Perfluorooctane sulfonate (PFOS), Nitrate. For most residents, a properly certified home filter at the kitchen tap is the most cost-effective way to reduce exposure to whatever's in your water. See our filter recommendations below, matched specifically to this utility's contaminant profile.
Quick actions for BOSTON residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for MWRA.
PFAS contamination
Severe concernPerfluorooctanoic acid (PFOA), Perfluorooctane sulfonate (PFOS) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 14.7 ppb, 147x above the EWG health guideline of 0.1 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 17.2 ppb, 115x above the EWG health guideline of 0.15 ppb.
Dichloroacetic acid significantly above health guideline
Moderate concernDichloroacetic acid detected at 11.0 ppb, 55x above the EWG health guideline of 0.2 ppb.
Contact MWRA
Reach the utility directly for service issues, water quality concerns, or to request your Consumer Confidence Report.
General Contact
Treatment Plant
Recommended water filters for BOSTON
Filters matched to the specific contaminants in this water supply.
Reverse Osmosis or NSF P473 certified carbon
$80-$750Activated carbon and RO are the only technologies proven to remove PFAS at certified levels.
Carbon block (NSF/ANSI 42 + 53)
$40-$750Activated carbon is highly effective for disinfection byproducts like TTHM and HAA5.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
Score breakdown
This utility's overall score of 60/100 breaks down across five weighted components. Read the full methodology →
Contaminants detected — international standards comparison
Every contaminant detected, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal (the strictest US benchmark). Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Haloacetic acids (HAA5) Disinfection byproduct |
14.7 ppb | 0.1 | 60.0 | 60 | — | — | — | 147× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
17.2 ppb | 0.15 | 80.0 | 100 | — | — | — | 115× over |
| Dichloroacetic acid Disinfection byproduct |
11.0 ppb | 0.2 | — | — | — | — | — | 55× over |
| Bromodichloromethane Disinfection byproduct |
3.25 ppb | 0.06 | — | — | — | — | — | 54× over |
| Chloroform Disinfection byproduct |
13.1 ppb | 0.4 | — | — | — | — | — | 33× over |
| Trichloroacetic acid Disinfection byproduct |
2.02 ppb | 0.1 | — | — | — | — | — | 20× over |
| Perfluorooctanoic acid (PFOA) PFAS |
0.832 ppt | 0.09 | 4.0 | 100 | 100 | 0.007 | — | 9.2× over |
| Dibromochloromethane Disinfection byproduct |
0.808 ppb | 0.1 | — | — | — | — | — | 8.1× over |
| Perfluorooctane sulfonate (PFOS) PFAS |
0.44 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | 1.5× over |
| Nitrate Inorganic |
0.141 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 1.0× over |
| Manganese Heavy metal |
6.63 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
1.7 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Barium Heavy metal |
7.39 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Aluminum Heavy metal |
4.43 ppb | 600.0 | — | 200 | — | 600 | — | Below guideline |
| Perfluorohexanoic Acid (PFHxA) PFAS |
0.505 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluoroheptanoic acid (PFHPA) PFAS |
0.413 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluorobutane sulfonate (PFBS) PFAS |
0.131 ppt | 2000.0 | — | — | — | — | — | Below guideline |
| Bromide Other |
12.2 ppb | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.291 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Nitrite Inorganic |
0.000554 ppm | — | 1.0 | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines (4th ed.), California OEHHA PHGs, EWG Tap Water Database.
MWRA service area
This water system serves 1 community in Suffolk County, Massachusetts. Click any city for its dedicated tap water quality page.
Find the right filter for BOSTON water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.