Boston's annual water report contains information for the regional supply and a separate Boston community letter. Read the local letter before turning a regional headline into a statement about an individual home. The groups of samples and the places where they were collected matter.
The 2025 MWRA report includes Boston Water and Sewer Commission's local lead results. Read that local table with its stated sample group and collection period.
Read the Boston letter beside the regional report
Boston's September/October 2025 table reports a lead 90th-percentile value of 22.5 parts per billion, above the 15 ppb action level stated for that round. Four of 33 samples were over that action level. The letter says these were homes known to have lead service lines.
These are the local figures from that sampling round, not a measurement of every Boston tap. An action-level comparison for a selected group should not be converted into a percentage chance that a visitor's glass contains lead. Nor should a general regional statement erase the local finding.
For a property question, keep the community name beside the figure. Another municipality's table on the same long report page is not a substitute for Boston's results. Check the community heading before quoting a number.
These homes were chosen for lead sampling
MWRA's lead-results explanation says regulatory sampling targets higher-risk homes with lead services, solder or fixtures. Water is sampled after at least six hours of stagnation. That protocol examines corrosion control under the stated conditions.
It is a selected sampling group, not a random census of all households. The result tells you something about that group under that protocol. Carry those conditions into any explanation of the figures rather than presenting them as ordinary water use at every address.
The same page separates regulatory samples from investigation samples taken after an inquiry or complaint. It also describes requested lead samples. A result from one of those activities needs its own collection details; it should not be added casually to the regulatory group.
One address can need a separate investigation
BWSC's water-service map identifies lead services using records and field inspections. It has an address search and directs customers to the commission for a material inspection.
A service-line record answers a pipe-material question. A water result answers a sampling question. If you are worried about a specific property, ask which one the record in front of you actually addresses, and what additional inquiry the commission recommends.
The annual report also identifies home plumbing as a possible source of lead. A service-line lookup therefore should not be treated as a report on every fixture inside a building. Give a household inquiry its full address, the relevant tap and any existing test's collection date.
Carry the sampling year into your conclusion
MWRA's older full-service report is the 2024 edition. Reading that page today does not turn its results into a new sampling round. Keep it separate from the 2025 report rather than merging figures with different reporting periods.
The 2025 Boston findings do not establish an individual tap's condition in 2026. For a current household concern, seek the relevant local investigation or sampling guidance. The Boston city guide provides general travel context; annual and property-specific evidence need their stated boundaries.
