Tap Water Quality Report
Tap water quality in WALTHAM, Massachusetts
Tap water in WALTHAM, Massachusetts receives a grade of F (55/100) from TapWaterSafety.org. It's served by WALTHAM WATER DEPARTMENT. The most significant water quality concerns are: PFAS contamination; Haloacetic acids (HAA9) significantly above health guideline; Haloacetic acids (HAA5)* significantly above health guideline; Chloroform significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in WALTHAM's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving WALTHAM.
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 (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 11.9 ppb, 198x above the EWG health guideline of 0.06 ppb.
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.
Chloroform significantly above health guideline
Moderate concernChloroform detected at 47.9 ppb, 120x above the EWG health guideline of 0.4 ppb.
Recommended filters for WALTHAM
Filters matched to the specific contaminants in WALTHAM's 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.
All contaminants detected in WALTHAM'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 |
11.9 ppb | 0.06 | — | — | — | — | — | 198× over |
| Haloacetic acids (HAA5)* Disinfection byproduct |
14.7 ppb | 0.1 | 60.0 | 60 | — | — | — | 147× over |
| Chloroform Disinfection byproduct |
47.9 ppb | 0.4 | — | — | — | — | — | 120× over |
| Bromodichloromethane Disinfection byproduct |
7.07 ppb | 0.06 | — | — | — | — | — | 118× 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 |
| Trichloroacetic acid* Disinfection byproduct |
2.02 ppb | 0.1 | — | — | — | — | — | 20× over |
| Dibromochloromethane Disinfection byproduct |
1.48 ppb | 0.1 | — | — | — | — | — | 15× over |
| Perfluorooctanoic acid (PFOA)* PFAS |
0.832 ppt | 0.09 | 4.0 | 100 | 100 | 0.007 | — | 9.2× over |
| Perfluorooctane sulfonate (PFOS)* PFAS |
0.44 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | 1.5× over |
| Nitrate Inorganic |
0.0804 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | Below guideline |
| Chlorate Disinfection byproduct |
106.8 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
7.18 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 |
| Strontium Radiological |
0.0388 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 |
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 WALTHAM WATER DEPARTMENT.