Arlington, Massachusetts
Arlington Water Quality
MWRA reservoir water through the Town's own pipes. By the end of 2025 Arlington had cut known lead services from thirty to three, cleared every galvanized-requiring-replacement line, and posted 2.79 ppb lead at the 90th percentile.
Lead services: 30 → 3 by year-end 2025. Lead 2.79 ppb at the 90th percentile.
The short answer
Arlington, Massachusetts drinks MWRA water, disinfected with chloramine. Its September 2025 lead result was 2.79 ppb at the 90th percentile — well under the 15 ppb action level — with zero of 20 homes over the limit.
The Town cut known lead services from 30 to three by year-end 2025 and cleared all galvanized-requiring-replacement lines. About 2,337 services remain unknown. Check the GIS inventory first; a tap test then tells you what in-house plumbing still contributes.
Get a free test
Tell us your Arlington, Massachusetts 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 Arlington water comes from
The same reservoirs as Boston, through the Town's own pipes.
Quabbin and Wachusett Reservoirs
Arlington receives all of its water from the MWRA. The Quabbin Reservoir sits about 65 miles west of Boston; the Wachusett about 35 miles west.
Treated at MWRA facilities
After MWRA treatment (ozone, UV, fluoride, corrosion control and monochloramine), water enters Arlington through five MWRA master meters.
Then Arlington's own distribution
About 130 miles of mains (6–20 inches), roughly 1,400 hydrants and 12,705 service connections. In 2025 the Town supplied 1,221 million gallons.
What the 2025 Arlington report actually says
Limits are fixed. Results are from MWRA's 2025 Drinking Water Test Results for Arlington, including the Town letter — system-level figures, not a reading at your tap. A later report supersedes them.
Lead — 2.79 ppb at the 90th percentile
Arlington's September 2025 round of 20 high-risk homes: 2.79 ppb at the 90th percentile (range 0.152–3.76 ppb). All samples stayed under the 15 ppb action level.
Copper — 104 ppb
90th percentile across the same homes (range 19.7–126 ppb) against a 1,300 ppb action level. No sample exceeded the copper action level.
Only three known lead services left
At year-end 2025 the inventory showed Lead 3, galvanized requiring replacement 0, and Unknown 2,337. That is down from 30 lead and 2 GRR on the October 2024 inventory.
1,248 unknowns cleared in 2025
Records review and inspection cut unknowns by 1,248. Letters went to every property still marked unknown, GRR or lead. The GIS inventory is at arlingtonma.gov/water.
Remaining lead lines scheduled for 2026
Property owners at the three remaining lead locations have been contacted. Investigation and replacement, if needed, are scheduled for 2026 under the Town's no-cost lead line removal program.
Monochloramine from MWRA
MWRA finishes with chloramine. That shapes filter choice more than any figure on Arlington's own letter.
Arlington MA next to Medford, Somerville and Cambridge
Nearby Medford crossed the lead action level in 2025 and entered a MassDEP consent order. Somerville reported 3.92 ppb with a replacement program nearly finished. Cambridge treats its own reservoir supply rather than buying MWRA water for households. Arlington's story is the inventory shrink — thirty known lead lines down to three.
Where these figures come from
Everything on this page traces to MWRA and the Town of Arlington Department of Public Works.
- MWRA — 2025 Drinking Water Test Results, with the Town of Arlington letter (PDF) — MWRA sources and treatment; Arlington's lead and copper results, inventory progress and remaining lead-line schedule.
- Town of Arlington — Water — the GIS service-line inventory and lead removal program page.
Matching treatment to the finding
Arlington's report supports checking your service line and a chloramine-aware filter choice — not a default equipment sale.
Check the GIS inventory first
Arlington publishes an online service-line map at arlingtonma.gov/water. If yours shows lead, GRR or unknown, the Town program comes before any filter.
No-cost lead line removal
Locations confirmed as lead are included in the Town's no-cost removal program. Contact the Water Division before hiring a private contractor for the public-side line.
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.
Arlington MA water, answered plainly
Where does Arlington's water come from?+
From the MWRA. Arlington receives treated Quabbin and Wachusett water through five master meters into the Town's own distribution system.
Did Arlington exceed the lead action level?+
No. The September 2025 letter shows 2.79 ppb at the 90th percentile against a 15 ppb action level, with zero of twenty homes over the limit. Copper also stayed under its action level.
How many lead services does Arlington still have?+
Three known lead services at year-end 2025, down from 30 on the October 2024 inventory. Galvanized requiring replacement is zero. About 2,337 services remain unknown.
How do I check my service line?+
Use the GIS inventory at www.arlingtonma.gov/water. For meters and connections call 781-316-3106; for bills 781-316-3102. MWRA is at 617-242-5323.
Is this the same as Arlington, Virginia?+
No. This page is Arlington, Massachusetts (Middlesex County), an MWRA community. Arlington, Virginia has a separate water page on this site under a different utility.
Where do these figures come from?+
MWRA's 2025 Drinking Water Test Results for Arlington, which includes the Town of Arlington Department of Public Works letter (PWS 3010000). 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 →Medford water quality
Next door: 2025 lead action-level exceedance and MassDEP ACO.
Learn more →Somerville water quality
MWRA water with a lead replacement program near done.
Learn more →Revere water quality
MWRA water with 362 known lead services still on the inventory.
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