Cambridge, MA: High Radon Risk — 59/100 (2026)
7 ZIP codes · 3 water systems · Updated 2026-06-03
For most households in Cambridge, MA tap water is adequate — the middle-tier grade reflects gaps in specific service areas.
How Cambridge Compares
Data: EPA SDWIS Last verified: 2026-06-03
Water Quality Map: Cambridge, MA
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Score Distribution
Distribution of water safety grades across Cambridge.
Cambridge Water: The Quick Version
- Average lead level: 0.008 mg/L.
- Homes built before 1986: 65% — older plumbing may contain lead solder.
- Estimated remediation: $2,671 per household.
- CDC health risk index: 9.88.
Water Systems Serving Cambridge
Residential addresses in Cambridge, MA are served by 3 primary water providers out of 3 systems in federal records. Each system maintains separate infrastructure and files its own EPA compliance reports, so service conditions are not uniform across the city.
Overview
We track water quality and home safety data for 7 ZIP codes in Cambridge, Massachusetts (population ~118,073), covering 3 community water systems serving approximately 874,906 people region-wide.
No EPA violations recorded across any ZIP codes in Cambridge — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Cambridge: C (59/100)
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
Cambridge water systems draw from: Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0080 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 1 (High Risk)
- Zone 1 (High): 7 ZIP codes
- Zone 2 (Moderate): 0 ZIP codes
- Zone 3 (Low): 0 ZIP codes
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 02138 | C | Cambridge Water Department | 118,214 |
| 02139 | C | Cambridge Water Department | 118,214 |
| 02140 | C | Cambridge Water Department | 118,214 |
| 02141 | C | Cambridge Water Department | 118,214 |
| 02142 | C | Cambridge Water Department | 118,214 |
| 02238 | C | Cambridge Water Department | 118,214 |
| 02239 | C | Cambridge Water Department | 118,214 |
All ZIP Codes in Cambridge
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 Cambridge
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 Cambridge's Housing Stock?
With 65% 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
Reading the housing age data for Cambridge — median build year 1948 — the overriding implication is that the plumbing materials inside a typical home here reflect pre-1986 construction standards. In practical terms, that means lead-soldered copper joints are common across much of the housing stock. Where those materials are present, water can leach lead as it moves through joints — a pathway that corrosion control treatment under federal rules is designed to reduce, though it cannot eliminate lead risk where the plumbing materials themselves contain lead.
Over half of homes in Cambridge 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.
Cambridge: Remediation Cost in Perspective
How much of a Cambridge home's value does documented remediation represent? A small fraction — the equity share here is in the low tier, and from a household financial perspective, most property owners are considering a commitment that fits comfortably within standard planning rather than a decision that rises to the level of a material budget event or significant equity consideration.
Remediation costs in Cambridge are relatively low compared to home values. The $1,800–$3,671 estimated range is a small fraction of median property value. Home values are 90% above the Massachusetts average.
Protecting Children from Lead in Cambridge
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.
Practically, the structural drivers in Cambridge — 65% pre-rule stock and citywide monitoring at or beyond the regulatory benchmark — make an in-home draw the practical way to translate aggregate averages into the specific conditions at one address.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Cambridge
Multiple flood events have been recorded for Cambridge through the NFIP — 82 claims in total, with 71% of ZIP codes in FEMA-designated zones — pointing to a flood exposure profile that merits inclusion in a water quality assessment without reaching high-severity planning territory.
Cambridge has a moderate flood history with 82 FEMA claims averaging $17,120 per payout. 71% 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>$2,671</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.
What You Can Do in Cambridge
- Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. An NSF-certified pitcher or under-sink filter removes most common contaminants.
- Check your home's plumbing. With 65% of homes built before 1986, lead solder is a real possibility.
Deep Dive Reports
Detailed analysis for Cambridge, MA