Chelsea, MA Water Safety: 88/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
Although water quality varies across any metro, Chelsea's systems collectively post above-average compliance scores for MA — and documented violations are few.
How Chelsea Compares
Data: EPA SDWIS Last verified: 2026-06-03
Chelsea Water: The Quick Version
- Average lead level: 0.0059 mg/L.
- Homes built before 1986: 75% — older plumbing may contain lead solder.
- Estimated remediation: $1,200 per household.
- CDC health risk index: 10.05.
Water Systems Serving Chelsea
Multiple utilities divide Chelsea, MA's water service — 2 leading providers among 2 on the federal register.
Overview
We track water quality and home safety data for 1 ZIP code in Chelsea, Massachusetts (population ~39,444), covering 2 community water systems serving approximately 2,698,319 people region-wide.
No EPA violations recorded across any ZIP codes in Chelsea — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Chelsea: A (88/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Chelsea water systems draw from: Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0059 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 3 (Low Risk)
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 02150 | A | Chelsea Water Department (mwra) | 38,319 |
All ZIP Codes in Chelsea
- 02150 [A]
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
CDC Health Data for Chelsea
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
How Old Is Chelsea's Housing Stock?
With 75% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Pre-1986 plumbing is not a rare legacy case in Chelsea — it's the dominant profile. The median build year of 1900 indicates a housing stock where lead-soldered copper joints are a common structural feature of residences across the city.
Over half of homes in Chelsea were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.
Source: U.S. Census Bureau ACS B25034.
Chelsea: Remediation Cost in Perspective
Across Chelsea, the equity share taken up by estimated remediation is small — a favorable ratio for most property owners.
Remediation costs in Chelsea are relatively low compared to home values. The $800–$1,800 estimated range is a small fraction of median property value. Home values are 15% below the Massachusetts average.
Protecting Children from Lead in Chelsea
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Despite citywide averages serving as the standard public reference point, those aggregates cannot resolve what is happening at one specific faucet — and where 75% of Chelsea homes come from before the solder rule or where utility samples sit at or above the action mark, the gap between system data and faucet reality matters more than it does in lower-exposure communities. An in-home draw closes that gap, with certified filtration through retailer networks available where confirmed faucet results warrant additional measures.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Chelsea
The NFIP claim record for Chelsea — 39 filed incidents — reflects genuine, recurring flood exposure rather than an isolated event or two. When a community accumulates flood claims at this volume and carries 100% of its ZIP codes inside FEMA-designated zones, flood history starts to factor into water quality planning in ways it doesn't for lower-exposure areas. Flooding introduces specific contamination pathways — runoff overwhelming treatment facility intake, surface water infiltrating private wells, and pressure disruptions in distribution systems allowing backflow — all of which become more relevant as flood frequency increases.
Chelsea has a moderate flood history with 39 FEMA claims averaging $4,343 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$1,200</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
Deep Dive Reports
Detailed analysis for Chelsea, MA