Tap Water Quality Report
Tap water quality in Boston, Massachusetts
Tap water in Boston, Massachusetts receives a grade of D (62/100) from TapWaterSafety.org. It's served by 2 public water systems, primarily MWRA. 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; Haloacetic acids (HAA9) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in Boston's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utilities serving Boston.
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.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 16.8 ppb, 281x above the EWG health guideline of 0.06 ppb.
EPA compliance record
Official U.S. EPA records for MWRA (system ID MA6000000) for the last 3 years. Checked 2026-10-07.
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Water systems serving Boston
Boston is served by 2 public water systems. Click any utility to see its complete grade card and treatment plant contact info.
MWRA
- PFAS contamination
- Haloacetic acids (HAA5) significantly above health guideline
- Total trihalomethanes (TTHMs) significantly above health guideline
BOSTON WATER AND SEWER COMMISSION (MWRA)
- PFAS contamination
- Haloacetic acids (HAA9) significantly above health guideline
- Haloacetic acids (HAA5)* significantly above health guideline
Recommended filters for Boston
Filters matched to the specific contaminants in Boston's water supply.
Filter certified for PFOA/PFOS (NSF/ANSI 53 or 58)
$180-$750Reverse osmosis and some carbon block filters reduce PFAS. Look for certification to NSF/ANSI 53 or 58 for PFOA/PFOS.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in Boston's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. 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 (HAA9) Disinfection byproduct |
16.8 ppb | 0.06 | — | — | — | — | — | 281× over |
| Haloacetic acids (HAA5)* Disinfection byproduct |
14.7 ppb | 0.1 | 60.0 | 60 | — | — | — | 147× over |
| 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 |
| 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 |
| Dichloroacetic acid Disinfection byproduct |
11.0 ppb | 0.2 | — | — | — | — | — | 55× over |
| Bromodichloromethane* Disinfection byproduct |
3.25 ppb | 0.06 | — | — | — | — | — | 54× over |
| Bromodichloromethane Disinfection byproduct |
3.25 ppb | 0.06 | — | — | — | — | — | 54× over |
| Chloroform* Disinfection byproduct |
13.1 ppb | 0.4 | — | — | — | — | — | 33× over |
| Chloroform Disinfection byproduct |
13.1 ppb | 0.4 | — | — | — | — | — | 33× over |
| Trichloroacetic acid* Disinfection byproduct |
2.02 ppb | 0.1 | — | — | — | — | — | 20× 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 |
| 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 |
| 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 |
| 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 |
| Nitrate Inorganic |
0.141 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 1.0× over |
| Chlorate Disinfection byproduct |
117.4 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
8.22 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Monochloroacetic acid* Disinfection byproduct |
1.7 ppb | 53.0 | — | — | — | — | — | 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 |
| 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 |
| Aluminum Heavy metal |
4.43 ppb | 600.0 | — | 200 | — | 600 | — | Below guideline |
| Perfluorohexanoic Acid (PFHxA)* PFAS |
0.505 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluorohexanoic Acid (PFHxA) PFAS |
0.505 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluoroheptanoic acid (PFHPA)* PFAS |
0.413 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 |
| Perfluorobutane sulfonate (PFBS) PFAS |
0.131 ppt | 2000.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.037 ppb | 1500.0 | — | — | — | — | — | 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 |
| 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, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from MWRA.
General Contact
Treatment Plant
ZIP codes served
Boston's public water systems serve the following ZIP codes: