Is Somerville, MA Tap Water Safe to Drink?
Yes, Somerville tap water is safe to drink. Hardness is low at 14 PPM, and no contaminants exceed health guidelines. Most homes here don't need treatment.
Hardness Scale: Where Somerville Falls
0Slightly
60Moderate
120Hard
180Very Hard
250Extreme
400+
How Somerville Compares
Somerville's water is 90% softer than the national average of 138 PPM - ranking in the bottom 98% for hardness nationwide. Most homes here do not need a softener. Within Massachusetts, it ranks #15 of 21 cities (26% below the state average of 19 PPM). Among cities (50k-100k), Somerville ranks #255 of 258 for hardness.
What Somerville's Water Means for Your Home
Hardness: 14 PPM - Low Concern
Somerville's water is soft at just 14 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. Somerville is softer than 98% of US cities. If you're thinking about water treatment in Somerville, contaminant filtration is the place to invest.
Contaminants & Safety
Disinfection byproducts are the notable finding here. Somerville's water has TTHMs at 17.2 ppb and HAA5 at 14.7 ppb — both within legal limits, but the EWG health guidelines are far stricter. These byproducts form when chlorine reacts with organic matter during treatment. A whole-house activated carbon filter reduces both chlorine and its byproducts. Want the full picture? Request your utility's annual Consumer Confidence Report.
What's in the Treatment Process
Somerville's surface water supply requires heavy chlorination to stay safe — but that creates a tradeoff. The treatment process generates disinfection byproducts: TTHMs at 17.2 ppb (22% of the legal limit, but 115x the EWG guideline) and HAA5 at 14.7 ppb (25% of the legal limit, but 147x 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. 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) | 14 PPM | < 60 PPM | No federal limit | ✓ OK |
| Total Dissolved Solids | 21 PPM | < 300 PPM | 500 PPM | ✓ OK |
| PFAS (total) | 0 ppt | — | No total limit | ✓ ND |
| ↳ PFOA | 0 ppt | 0 ppt | 4 ppt (2024) | ✓ OK |
| ↳ PFOS | 0 ppt | 0 ppt | 4 ppt (2024) | ✓ OK |
| Lead | 3.9 ppb | 0 ppb (no safe level) | 15 ppb (10 ppb in 2027) | ✓ Low |
| Chlorine / Chloramine | 1.5 mg/L | Taste threshold ~1.0 | 4.0 mg/L | ✓ Normal |
| Nitrate | 0.13 mg/L | 5 mg/L | 10 mg/L | ✓ OK |
Good news for Somerville residents. Your water quality is generally good. Most homes in this area do not need a water softener. If you have concerns about lead (especially in buildings constructed before 1986) or chlorine taste, a point-of-use filter is the most practical and cost-effective solution.
Quick Fix for Chlorine: Shower Filter
At 1.5 mg/L chlorine, many Somerville 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 Somerville
City-wide data is a solid starting point, but your specific tap might differ based on plumbing age, distance from the treatment plant, or seasonal changes.
Free option: Request Massachusetts Water Resources Authority's annual Consumer Confidence Report for official city-level data.
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About Somerville's Water Supply
Water Utility: Massachusetts Water Resources Authority
Water Source: MWRA Quabbin & Wachusett Reservoirs (Surface Water)
Population Served: 81,045
Hardness: 14 PPM (0.8 grains per gallon)
Somerville's drinking water comes from surface sources — MWRA Quabbin & Wachusett Reservoirs. 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 81,000 residents.
Water quality can vary by neighborhood and season. For your exact numbers, request Massachusetts Water Resources Authority'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 Massachusetts Water Resources Authority in Somerville, MA, including ZIP codes:
02143, 02144, 02145
If your ZIP code is listed above, this report covers your water supply. Water quality may vary slightly by neighborhood.
Compare Somerville to Other Massachusetts Cities
Frequently Asked Questions About Somerville Water
Is Somerville tap water safe to drink?
Where does Somerville's water come from?
Do I need a water softener in Somerville?
What are disinfection byproducts in Somerville's water?
Why does Somerville water taste like chlorine?
Can I drink Somerville tap water straight from the faucet?
What water filter is best for Somerville?
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 Somerville Homeowners Actually Buy
Common purchases for homes with 14 PPM water.
Affiliate disclosure: we may earn a commission. Selection based on Somerville's water data.