Water Quality in Danbury, CT

Danbury's water has PFAS above EPA limits (6 ppt). An activated carbon filter can reduce PFAS levels. Read below for a full breakdown.

Danbury Water · Source: Reservoirs, wells · Serves 86,518 residents

50
Hardness (PPM)
83
TDS (PPM)
1.3
Chlorine (mg/L)
6
PFAS (ppt)
3
Lead (ppb)
50 PPM 0 400 Slightly Hard
CONTAMINANT LEVELS Hardness 50 PPM TDS 83 PPM PFAS 6 ppt Lead 3 ppb Chlorine 1.3 mg/L Nitrate 2 mg/L

Hardness Scale: Where Danbury Falls

Soft 060120180250400+
PFAS above EPA limit

Danbury's western Connecticut water sources produce soft water from granite and gneiss bedrock geology.

What Danbury's Water Means for Your Home

Danbury's water is slightly hard at 50 PPM. At this level, hard water is not a significant concern for most households. Scale buildup is minimal, and a water softener would provide little measurable benefit. If you are considering water treatment in Danbury, focus on contaminant filtration rather than softening.

PFAS contamination is a significant concern in Danbury. At 6 parts per trillion, levels exceed the EPA's 2024 maximum contaminant level of 4 ppt. PFAS are synthetic chemicals that do not break down in the environment or the human body, which is why they are called "forever chemicals." Long-term exposure has been associated with increased cancer risk, thyroid disruption, and immune system effects. A whole-house activated carbon filter or point-of-use reverse osmosis system can reduce PFAS to safe levels. Look for NSF P473 certification when comparing products.

ContaminantDetectedHealth GuidelineLegal LimitStatus
Hardness (as CaCO₃)50 PPM< 60 PPMNo federal limit✓ OK
Total Dissolved Solids83 PPM< 300 PPM500 PPM✓ OK
PFAS (total)6 ppt4 ppt (EPA)4 ppt (2024)⚠ Above limit
Lead3 ppb0 ppb (no safe level)15 ppb (action level)✓ Low
Chlorine / Chloramine1.3 mg/LTaste threshold ~1.04.0 mg/L✓ Normal
Nitrate2 mg/L5 mg/L10 mg/L✓ OK

Recommendations for Danbury Homes

🔬 Activated Carbon Filter for PFAS
PFAS detected at 6 ppt, above the EPA maximum contaminant level of 4 ppt. PFAS are linked to cancer, thyroid disease, and immune system effects with long-term exposure. A whole-house granular activated carbon (GAC) filter or a point-of-use reverse osmosis system can reduce PFAS. Look for NSF P473 certification, which specifically tests for PFAS removal.
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About Danbury's Water Supply

Water Utility: Danbury Water

Water Source: Reservoirs, wells

Population Served: 86,518

Hardness: 50 PPM (2.9 grains per gallon)

Water quality can vary by neighborhood and season. The values above represent typical averages reported by Danbury Water. To get exact numbers for your address, request a copy of the most recent Consumer Confidence Report (CCR) from your utility, or have your water independently tested.

Compare Danbury to Other Connecticut Cities

Bridgeport

41 PPM · Slightly Hard

Hartford

48 PPM · Slightly Hard

Stamford

22 PPM · Slightly Hard

New Haven

34 PPM · Slightly Hard

Waterbury

55 PPM · Slightly Hard

Frequently Asked Questions About Danbury Water

Is Danbury tap water safe to drink?
Danbury's water meets EPA legal standards for drinking water safety. However, legal limits and health-optimal levels are different things. PFAS levels exceed the 2024 EPA health standard, which is a concern for long-term exposure. Review the contaminant table above for specific numbers and how they compare to both legal limits and health guidelines.
Do I need a water softener in Danbury?
Probably not. At 50 PPM, Danbury's water is on the softer end. Most homes will not experience noticeable scale buildup. That said, if you have high-end fixtures, a glass shower enclosure, or a tankless water heater, even mild hardness can leave mineral deposits over time. A salt-free conditioner is a low-cost insurance policy in that case.
What water filter is best for Danbury?
The best filter depends on which contaminants you want to address. For PFAS, look for a filter with NSF P473 certification. Granular activated carbon (GAC) and reverse osmosis systems are both effective. Standard carbon pitcher filters may not remove PFAS adequately. For chlorine taste and odor, an activated carbon filter is effective and affordable, available as under-sink, countertop, or whole-house systems. See our softener vs. filter guide to understand the difference between these categories.
Where does Danbury's water come from?
Danbury's drinking water is sourced from Reservoirs, wells and treated by Danbury Water. Danbury's western Connecticut water sources produce soft water from granite and gneiss bedrock geology..
What is the hardness of Danbury water in grains per gallon?
Danbury's water hardness is 2.9 grains per gallon (GPG), which equals 50 parts per million (PPM). This is classified as slightly hard. To convert: 1 GPG = 17.1 PPM.
Does Danbury water damage tankless water heaters?
At 2.9 GPG, Danbury's water is unlikely to cause significant issues for tankless water heaters. However, if you notice reduced flow or efficiency over time, scale buildup could be a factor. Annual flushing with vinegar is good maintenance regardless of hardness.
Is Danbury water safe for babies and infants?
Danbury's water meets all EPA safety standards and is generally considered safe for preparing infant formula. The hardness minerals (calcium and magnesium) are not harmful. If your home has older plumbing, running cold water for 30 seconds before use is a good precaution to flush any lead from pipes.

Data sources. Water quality data compiled from EPA SDWIS, EWG Tap Water Database, USGS water hardness studies, and the Danbury Water Consumer Confidence Report. Hardness and contaminant levels represent typical average values and may vary by neighborhood and season. Last updated: 2026-02-12.