Nitrate in Connecticut well water
In Connecticut, 17% of 3,518 tested private well samples exceeded the EPA limit for nitrate (10 mg/L).
Nitrate reaches wells from fertilizer, septic systems and manure. Above the limit it can cause methemoglobinemia (blue baby syndrome) in infants under six months, and long-term exposure is associated with some cancers. Shallow and dug wells near farmland or dense septic systems are most at risk.
Check your nitrate number
Type the value from your lab report. It is compared to the EPA limit, the same way the full interpretation does it.
Test your Connecticut well for nitrate
Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.
Order the Tap Score well water test kit, from $209Already tested? Upload the report
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Systems that remove nitrate
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Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.
For nitrate
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
For nitrate
Aquasana SmartFlow reverse osmosis
under-sink or countertop, about $225
Certified to NSF/ANSI 58 and 53 to reduce arsenic (96%, pentavalent), fluoride (90%), lead (99%), nitrate, nitrite and PFOA/PFOS at the kitchen tap, with a remineralizer.
Rather have it installed and sized for your well? Book a free in-home water test with a licensed local company.
Where to get a well tested for nitrate in Connecticut: certified labs, state programs and prices.
By county, from individual samples
Public monitoring samples against the EPA limit (10 mg/L); counties with at least 30 samples.
| County | Above EPA limit | Samples | Detected | Median | Highest |
|---|---|---|---|---|---|
| Southeastern Connecticut | 1,024 | 99% | 4 | 113 mg/L | |
| South Central Connecticut | 219 | 96% | 4.29 | 66 mg/L | |
| Capitol | 995 | 95% | 3 | 170 mg/L | |
| Naugatuck Valley | 455 | 92% | 1.8 | 84.2 mg/L | |
| Western Connecticut | 219 | 99% | 0.83 | 46 mg/L | |
| Lower Connecticut River Valley | 167 | 93% | 0.381 | 30 mg/L | |
| Northeastern Connecticut | 179 | 98% | 0.971 | 41 mg/L | |
| Greater Bridgeport | 45 | 91% | 0.67 | 59 mg/L | |
| Northwest Hills | 215 | 94% | 0.153 | 28 mg/L |
- Enfield, Capitol Planning Region32% of 31
- Ellington, Capitol Planning Region32% of 59
- Griswold, Southeastern Connecticut Planning Region30% of 33
- East Lyme, Southeastern Connecticut Planning Region30% of 797
- East Windsor, Capitol Planning Region29% of 38
- Windsor, Capitol Planning Region27% of 37
- New Haven, South Central Connecticut Planning Region27% of 64
- South Windsor, Capitol Planning Region24% of 38
- Mansfield, Capitol Planning Region23% of 30
- Southbury, Naugatuck Valley Planning Region23% of 44
- Hamden, South Central Connecticut Planning Region21% of 34
- Manchester, Capitol Planning Region17% of 259
- Waterbury, Naugatuck Valley Planning Region13% of 32
- Southington, Capitol Planning Region11% of 44
- Waterford, Southeastern Connecticut Planning Region10% of 79
- Portland, Lower Connecticut River Valley Planning Region9% of 34
- Vernon, Capitol Planning Region9% of 46
- Avon, Capitol Planning Region9% of 47
- Newtown, Western Connecticut Planning Region8% of 61
- Woodbury, Naugatuck Valley Planning Region8% of 245
Sources
- Individual samples from the USGS Water Quality Portal and state monitoring, summarized per geography. nitrate counts and shares are listed on each county and town page with their sources.
Analysis: Nitrate in private wells, decade by decade, from the same public records.