Medford, Massachusetts
Medford Water Quality
MWRA reservoir water through Medford's own pipes. The City's 2025 letter shows a lead action-level exceedance — 15.5 ppb at the 90th percentile — and a MassDEP consent order that sets the replacement schedule.
Lead 15.5 ppb at the 90th percentile in 2025 — three of twenty homes over the action level.
The short answer
Medford drinks MWRA water from the Quabbin and Wachusett Reservoirs, disinfected with chloramine. Its 2025 lead result was 15.5 ppb at the 90th percentile — above the 15 ppb action level — with three of 20 homes over the limit.
The City entered a MassDEP Administrative Consent Order in 2025 that sets how many lead and unknown services it must identify and replace each year, and it offers a $1,000 rebate toward private-side lead service replacement. Check your service line first; a tap test then tells you what in-house plumbing still contributes.
Get a free test
Tell us your Medford address. We confirm coverage first, then schedule a licensed technician to test at your tap — no charge, no obligation.
What filtration does — and does not
Softening, carbon and reverse osmosis solve different problems. A filter is not a substitute for replacing a lead service line.
Where Medford water comes from
The same reservoirs as Boston, through Medford's own pipes.
Quabbin and Wachusett Reservoirs
Medford buys treated water from the MWRA, whose sources are the Quabbin and Wachusett Reservoirs in central and western Massachusetts.
Treated at the Carroll plant
MWRA's John J. Carroll Water Treatment Plant in Marlborough disinfects with ozone and UV, adds fluoride, adjusts pH and alkalinity to reduce lead corrosion, and finishes with monochloramine.
Then Medford's own distribution
The City's Department of Public Works takes water from the MWRA supply and delivers it through Medford's network of pipes, valves, hydrants and service lines.
What the 2025 Medford report actually says
Limits are fixed. Results are from MWRA's 2025 Drinking Water Test Results for Medford, including the City letter — system-level figures, not a reading at your tap. A later report supersedes them.
Lead — 15.5 ppb at the 90th percentile
Medford's single 2025 round of 20 homes: 15.5 ppb at the 90th percentile, above the 15 ppb action level. The range ran from below 0.075 to 21.8 ppb.
Three homes over the action level
Three of twenty samples exceeded 15 ppb. Under the Lead and Copper Rule, nine of ten sampled homes must stay under the action level.
MassDEP Administrative Consent Order (2025)
The Department entered an ACO with MassDEP in 2025 that sets annual identification targets for lead and unknown services, a minimum number of lead service replacements each year, and a reporting schedule.
Copper — 64.1 ppb
90th percentile across the same 20 homes (range 5.91–116 ppb), against a 1,300 ppb action level. No sample exceeded the copper action level.
Coliform — met every month
DPW samples eighteen sites four times a month for chlorine residual, temperature and total coliform. Medford stayed under the 5% monthly positive limit every month in 2025.
Monochloramine from MWRA
MWRA finishes with chloramine. That shapes filter choice more than any figure on Medford's own letter.
Medford next to Somerville, Malden and Boston
Next door, Somerville also drinks MWRA water but reported 3.92 ppb lead and a replacement program nearly finished. Malden exceeded the action level in fall 2025 at 17.9 ppb while replacing more than 330 lead services that year. Boston had its own 2025 lead exceedance on the same MWRA supply. Same reservoirs; different pipes and different replacement schedules.
Where these figures come from
Everything on this page traces to MWRA and the City of Medford Department of Public Works.
- MWRA — 2025 Drinking Water Test Results, with the City of Medford letter (PDF) — MWRA sources, treatment and detected contaminants; Medford's lead and copper results, ACO language, rebate programs and coliform compliance.
- City of Medford — Lead in Water — the service line inventory spreadsheet and related program links.
Matching treatment to the finding
Medford's report supports checking your service line and a chloramine-aware filter choice — not a default equipment sale.
Look up your service line first
The City posts its lead service line inventory as a downloadable spreadsheet on the Water & Sewer lead page. If yours shows lead, galvanized or unknown, the City's programs come before any filter.
$1,000 private-side rebate
Using an MWRA loan, Medford offers a $1,000 rebate when an owner replaces a private lead service. When a contractor replaces the private side, the City will replace the City-side service at the same time at City expense.
Certified lead filter as a stopgap
Until a lead service is replaced, a filter certified to reduce lead at the kitchen tap is the practical stopgap — not a substitute for the pipe.
Chloramine taste: catalytic carbon or RO
Ordinary carbon handles free chlorine better than chloramine. If taste or odour is the complaint, catalytic carbon or reverse osmosis is the right tool.
How the free test works
A licensed technician tests at your kitchen tap, walks the plumbing, and tells you which of the findings above applies to your house and which does not. There is no charge and no obligation.
Seamless Home is the licensed contractor of record on the work that follows. Installation is performed by vetted installing partners engaged as our subcontractors, and the workmanship obligation stays with us. Coverage is confirmed per service area rather than promised as blanket availability.
What a water treatment job with us covers
Installation and replacement of whole-home and point-of-use treatment, specified against what your water actually contains.
Sediment filtration
Installation of the first stage that protects everything downstream of it, sized to the service line and the household draw.
Softening
Installation of ion-exchange softening where hardness is the problem, including the drain connection the plumbing code treats as indirect waste.
Carbon filtration
Installation of carbon stages for taste, odour and disinfection by-products, specified from your utility's own water quality report.
Reverse osmosis
Point-of-use installation at the kitchen sink where the target is dissolved solids rather than whole-home flow.
Disinfection
Installation of UV or equivalent treatment where the supply is a private well or is otherwise not continuously disinfected.
System replacement
Replacing equipment that has reached the end of its service life, including the discharge and air gap details an inspector looks at.
This is installation and replacement work, specified from a published water quality report or a test of your supply — not from a sales chart. Coverage is confirmed per service area rather than promised as blanket availability.
What the work actually looks like
Treatment equipment is plumbing. Most of the job is the connection, the drain and the code detail behind it.
Medford water, answered plainly
Where does Medford's water come from?+
From the MWRA. Medford buys treated water from the Quabbin and Wachusett Reservoirs, treated at the John J. Carroll Water Treatment Plant in Marlborough and delivered into the City's own distribution system.
Did Medford exceed the lead action level?+
Yes, in 2025. The City's letter in MWRA's report shows a 90th percentile of 15.5 ppb against a 15 ppb action level, with three of twenty sampled homes over the limit. Copper stayed well under its action level.
What is the Administrative Consent Order?+
In 2025 Medford DPW entered an Administrative Consent Order with MassDEP that requires annual identification of lead and unknown service lines, a minimum number of lead service replacements each year, and regular reporting to DEP.
How do I check my service line?+
The City of Medford posts its lead service line inventory on its Water & Sewer lead-in-water page as a downloadable spreadsheet under Additional Links. For replacement help, the City letter lists Water Quality at 781-393-2561 and Engineering for confirmed lead services.
Does Medford use chlorine or chloramine?+
Chloramine. MWRA disinfects with monochloramine before the water reaches Medford's meters.
Where do these figures come from?+
MWRA's 2025 Drinking Water Test Results for Medford, which includes the City of Medford Department of Public Works letter (PWS 3176000). Third-party aggregators are not used. A later report supersedes these figures.
Related resources
Home water purification and treatment
The national service page behind this one.
Learn more →Malden water quality
Next door: fall 2025 lead exceedance and 330+ replacements.
Learn more →Somerville water quality
MWRA water with a lead replacement program near done.
Learn more →Boston water quality
The same MWRA water and Boston's 2025 lead exceedance.
Learn more →All home services
Water, battery, HVAC and solar under one licensed contractor of record.
Learn more →Get a free test at your tap
A licensed technician tests at your kitchen tap and tells you which findings apply to your house — lead from older plumbing, chloramine taste or none of them. No charge, no obligation, and coverage confirmed at your address first.
Get a free test