Hardness
Moderately Hard
83 PPM · 4.9 GPG
Local water dashboard
Official source aggregationWater quality in Danbury, CT 06811
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Fairfield County.
1 active health-based violation
- Primary matched system
- Danbury Water Department
- Source water
- Surface water + Groundwater influenced by surface water + Groundwater
- County
- Fairfield County
- Profile updated
At a glance
What the current records say
EPA quarter 2026Q2
Compliance screen
Review needed
1 active health-based record
Lead 90th percentile
0 mg/L
0% of action level
Utility match
10 systems
Serves 62,055 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
83 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
83
mg/L as CaCO₃ equivalent
Grains per gallon
4.9
1 GPG ≈ 17.1 PPM
What this means at home
At 83 PPM, mineral scale can build up on fixtures and heating elements, reduce soap lather, and leave visible spotting. Hardness is primarily an aesthetic and appliance concern—not itself a tap-water safety rating.
USGS sites used
143
Nearest site
4.9 mi
Observation range
Jan 4, 2016–Jun 3, 2026
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: STILL RIVER AT ROUTE 7 AT BROOKFIELD CENTER, CT (Stream).USGS source documentation ↗
Regional context
Is 06811 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Danbury median
83 PPM
About the same2 indexed ZIP readings · Range 83–83.6 PPM
Connecticut median
53 PPM
30 PPM higher98 indexed ZIP readings · Range 42.8–114 PPM
EPA benchmark screen
Contaminant snapshot
Available numerical results from associated SDWIS community water systems, compared with the applicable action level or federal MCL. Federal measured-value coverage is incomplete.
1 pass1 fail
Lead (PB90)
0 mg/L
Reported Dec 31, 2026
Copper (CU90)
1.51 mg/L
Reported Dec 31, 2023
Numerical coverage
2 comparable results
Missing values remain blank; absence is not treated as a pass.
Lead (90th percentile)
Measured in mg/L
Local 0
EPA limit 0.015
Copper (90th percentile)
Measured in mg/L
Local 1.51
EPA limit 1.3
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 114
- Health-based
- 4
- Active health-based
- 1
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Lead and Copper Rule | CT0340141 | Unaddressed | Jan 1, 2026 |
| Revised Total Coliform Rule | CT0347031 | Resolved | Dec 1, 2025through Dec 31, 2025 |
| Consumer Confidence Rule | CT0340181 | Resolved | Jul 1, 2025through Jul 3, 2025 |
| Consumer Confidence Rule | CT0340141 | Resolved | Jul 1, 2025through Jul 6, 2025 |
| Lead and Copper Rule | CT0340151 | Resolved | Apr 1, 2025through Apr 8, 2025 |
| CARBON, TOTAL | CT0090011 | Resolved | Jan 1, 2025through Jan 31, 2025 |
| CARBON, TOTAL | CT0090011 | Resolved | Jan 1, 2025through Jan 31, 2025 |
| Arsenic | CT0090011 | Archived | Jan 1, 2025through Dec 31, 2025 |
| Cadmium | CT0090011 | Archived | Jan 1, 2025through Dec 31, 2025 |
| Chromium | CT0090011 | Archived | Jan 1, 2025through Dec 31, 2025 |
| Mercury | CT0090011 | Archived | Jan 1, 2025through Dec 31, 2025 |
| Beryllium, Total | CT0090011 | Archived | Jan 1, 2025through Dec 31, 2025 |
| Thallium, Total | CT0090011 | Archived | Jan 1, 2025through Dec 31, 2025 |
| Selenium | CT0090011 | Archived | Jan 1, 2025through Dec 31, 2025 |
| 1,2,4-Trichlorobenzene | CT0090011 | Resolved | Jan 1, 2025through Dec 31, 2025 |
| Vinyl chloride | CT0090011 | Resolved | Jan 1, 2025through Dec 31, 2025 |
| 1,2-Dichloroethane | CT0090011 | Resolved | Jan 1, 2025through Dec 31, 2025 |
| 1,1,1-Trichloroethane | CT0090011 | Resolved | Jan 1, 2025through Dec 31, 2025 |
| Carbon tetrachloride | CT0090011 | Resolved | Jan 1, 2025through Dec 31, 2025 |
| 1,1,2-Trichloroethane | CT0090011 | Resolved | Jan 1, 2025through Dec 31, 2025 |
No reported violation does not prove that every contaminant was tested or absent; SDWIS measured values are incomplete and lag state records.
Solutions matcher
Your personalized water action plan
Matched to Danbury ZIP 06811 using 83 PPM nearby hardness and 2 reported measurement benchmarks.
Drinking water protection
Under-Sink Reverse Osmosis System
Copper (90th percentile) has a measured benchmark flag or active health-based SDWIS record in this profile.
A certified multi-stage RO system targets a broader range of dissolved contaminants at the kitchen tap.
Explore under-sink filtrationAffiliate disclosure: we may earn a commission from qualifying purchases, at no added cost to you. Product matching is educational and does not replace certified water testing.
Nearby indexed reports
Compare ZIPs in Danbury
Estimates can differ across a city because monitoring locations and associated systems differ.
Frequently asked
Water questions for Danbury
Is tap water safe in Danbury?+
EPA ECHO reports 1 active health-based violation among the associated community water systems. Review the affected utility's current notice and Consumer Confidence Report.
How hard is the water?+
Nearby USGS observations produce an estimate of 83 PPM, or 4.9 grains per gallon, classified as moderately hard. This is not a household tap measurement.
Do I need a water softener?+
There is no high-hardness trigger in this profile. Confirm with a tap test before buying equipment.