Is Cambridge, MA Tap Water Safe to Drink?
Cambridge tap water is legally compliant, but one contaminant exceeds health guidelines. Specifically: PFAS above EPA limits (PFOA: 4.8 ppt — limit is 4 ppt each). A point-of-use filter is recommended for drinking and cooking water.
Hardness Scale: Where Cambridge Falls
0Slightly
60Moderate
120Hard
180Very Hard
250Extreme
400+
How Cambridge Compares
Cambridge's water is 89% softer than the national average of 138 PPM - ranking in the bottom 97% for hardness nationwide. Most homes here do not need a softener. Within Massachusetts, it ranks #11 of 21 cities (21% below the state average of 19 PPM). Among mid-size cities (100k-200k), Cambridge ranks #181 of 189 for hardness.
What Cambridge's Water Means for Your Home
Hardness: 15 PPM - Low Concern
Cambridge's water is soft at just 15 PPM. That's good news for your plumbing, appliances, and skin. Scale buildup is a non-issue here, and a water softener would be a waste of money. Cambridge is softer than 97% of US cities. If you're thinking about water treatment in Cambridge, contaminant filtration is the place to invest.
Contaminants & Safety
Forever chemicals (PFAS) are worth watching here. Cambridge has PFOA at 4.8 ppt, exceeding the EPA's 2024 limit of 4 ppt per compound. PFAS are synthetic compounds that accumulate in your body over time. A certified carbon filter or reverse osmosis system with NSF P473 certification is the most effective protection. See the regulatory timeline.
What's in the Treatment Process
Cambridge's surface water supply requires heavy chlorination to stay safe — but that creates a tradeoff. The treatment process generates disinfection byproducts: TTHMs at 11.6 ppb (14% of the legal limit, but 77x the EWG guideline) and HAA5 at 6.54 ppb (11% of the legal limit, but 65x the EWG guideline). These are within legal limits, but the EWG sets much tighter thresholds based on cancer-risk research. A whole-house activated carbon filter reduces both chlorine and byproducts.
Chromium-6 was detected at 0.0563 ppb, which is 2.8x the EWG health guideline. There's no separate federal limit for chromium-6, only total chromium. A reverse osmosis system is the most effective removal method. All measurements are within federal legal limits. The EWG guidelines represent a more conservative, health-based standard.
| Contaminant | Detected | Health Guideline | Legal Limit | Status |
|---|---|---|---|---|
| Hardness (as CaCO₃) | 15 PPM | < 60 PPM | No federal limit | ✓ OK |
| Total Dissolved Solids | 18 PPM | < 300 PPM | 500 PPM | ✓ OK |
| PFAS (total) | 11.4 ppt | — | No total limit | Detected |
| ↳ PFOA | 4.8 ppt | 0 ppt | 4 ppt (2024) | ⚠ Exceeds |
| ↳ PFOS | 0 ppt | 0 ppt | 4 ppt (2024) | ✓ OK |
| Lead | 8 ppb | 0 ppb (no safe level) | 15 ppb (10 ppb in 2027) | ⚠ Elevated |
| Chlorine / Chloramine | 1.6 mg/L | Taste threshold ~1.0 | 4.0 mg/L | ✓ Normal |
| Nitrate | 0.35 mg/L | 5 mg/L | 10 mg/L | ✓ OK |
Recommendations for Cambridge Homes
Recommended Filter for Cambridge
PFAS exceed EPA limits (PFOA: 4.8 ppt — limit: 4 ppt each). A certified filter reduces these contaminants effectively.
Quick Fix for Chlorine: Shower Filter
At 1.6 mg/L chlorine, many Cambridge residents notice dry skin, brittle hair, and that "pool smell" in the shower. A shower filter installs in 5 minutes, no tools needed.
How to Test Your Water in Cambridge
With PFAS at 11.4 ppt in Cambridge's supply, confirming your home's specific levels is especially important. PFAS vary by neighborhood and can concentrate differently depending on your position in the distribution system.
Free option: Request Cambridge Water Department's annual Consumer Confidence Report for official city-level data.
📊 Already Tested Your Water?
City averages miss neighborhood-level variation. Share your results to help your neighbors get better data.
We review every submission before publishing. Your ZIP is shown; your identity is not.
About Cambridge's Water Supply
Water Utility: Cambridge Water Department
Water Source: Fresh Pond & MWRA reserves (Surface Water)
Population Served: 118,214
Hardness: 15 PPM (0.9 grains per gallon)
Cambridge's drinking water comes from surface sources — Fresh Pond & MWRA reserves. Surface water requires more extensive treatment than groundwater, including coagulation, filtration, and disinfection. This heavier chlorination is why disinfection byproducts tend to be higher in surface-supplied systems. On the upside, surface sources often deliver softer water than deep aquifers. The system serves 118,000 residents.
Water quality can vary by neighborhood and season. For your exact numbers, request Cambridge Water Department's Consumer Confidence Report (CCR) or test your own tap.
ZIP Codes Covered by This Report
This water quality data applies to all areas served by Cambridge Water Department in Cambridge, MA, including ZIP codes:
02130, 02134, 02138, 02139, 02140, 02141, 02142, 02238, 02445, 02446, 02447
If your ZIP code is listed above, this report covers your water supply. Water quality may vary slightly by neighborhood.
Compare Cambridge to Other Massachusetts Cities
Frequently Asked Questions About Cambridge Water
Is Cambridge tap water safe to drink?
Where does Cambridge's water come from?
Do I need a water softener in Cambridge?
How do I remove PFAS from Cambridge tap water?
What water filter is best for Cambridge?
Is Cambridge water safe for babies and infants?
What are disinfection byproducts in Cambridge's water?
Is chromium-6 in Cambridge's water?
Data sources: Lead and copper data from EPA Safe Drinking Water Act LCR reporting. Contaminant data from utility-reported testing results. PFAS data from EPA UCMR5 (2023–2025). Hardness from USGS and municipal reports. Data reflects system-level testing results and may not match your specific tap due to neighborhood plumbing, season, or recent utility changes. For your utility's latest results, request their Consumer Confidence Report (CCR). Our methodology. Last updated: 2026-02-24.
What Cambridge Homeowners Actually Buy
Prioritized for contaminant reduction for homes with 15 PPM water and PFAS above EPA limits.
Affiliate disclosure: we may earn a commission. Selection based on Cambridge's water data.