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EPA ID MA3035000 · checked 16 Oct 2026

Boston tap water: what EPA testing found

Boston Water and Sewer Commission (EPA record: BOSTON WATER AND SEWER COMMISSION (MWRA)) serves 675,647 people in MA from surface water purchased.

What the data shows

PFAS and lithium (EPA UCMR 5)

120 results from 1 sampling points, 10 Jan 2024 to 22 Oct 2024. Averages count results below EPA’s reporting level as zero, as the PFAS rule does. Every number links to EPA’s UCMR 5 Data Finder (search PWSID MA3035000). Limits: EPA PFAS rule.

ContaminantDetected inHighest resultAverageEPA limit
PFOA0 of 4not detected0 ng/L4 ng/L
PFOS0 of 4not detected0 ng/L4 ng/L
PFHxS0 of 4not detected0 ng/L10 ng/L*
PFNA0 of 4not detected0 ng/L10 ng/L*
HFPO-DA0 of 4not detected0 ng/L10 ng/L*
Lithium0 of 4not detected0 µg/Lnone (screening level 10 µg/L)

* PFHxS, PFNA and HFPO-DA limits (and the PFAS hazard index) are in the rule, but EPA proposed on 20 May 2026 to rescind them; not final as of 16 Oct 2026. UCMR 5 results are screening data, not compliance results: compliance uses quarterly running averages from 2029. Source file: EPA UCMR 5 occurrence data (dated 15 Oct 2026).

Health-based violations since 2016

Period beganContaminant or ruleViolationMeasuredStatus
1 Nov 2020Lead and Copper RuleLead Service Line Replacement (LSLR)–Open

Source: EPA SDWIS via Envirofacts and the ECHO report for MA3035000, retrieved 16 Oct 2026.

Hardness

0.8 grains per gallon (average, 2025), from the utility’s water report checked 16 Oct 2026. Size a softener for this water.

Places and ZIP codes served

Boston, Dorchester, Allston, Brighton, Charlestown, Dorchester Center, Hyde Park, Jamaica Plain, Mattapan, Readville, Roslindale, Roxbury, Roxbury Crossing, West Roxbury.

02108 02109 02110 02111 02112 02113 02114 02115 02116 02117 02118 02119 02120 02121 02122 02123 02124 02125 02126 02127 02128 02129 02130 02131 02132 02133 02134 02135 02136 02137 02163 02196 02199 02201 02203 02204 02205 02206 02210 02211 02212 02215 02217 02222 02241 02283 02284 02293 02297 02298

ZIP codes the system reported to EPA for UCMR 5; place names from GeoNames (CC BY 4.0). A ZIP code can be split between systems.