Nitrate in Delaware well water
In Delaware, 30% of 2,631 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 Delaware 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 Delaware: 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 |
|---|---|---|---|---|---|
| Sussex | 1,465 | 89% | 7.4 | 184 mg/L | |
| Kent | 342 | 75% | 2.13 | 88.1 mg/L | |
| New Castle | 824 | 70% | 2.79 | 138 mg/L |
- Milton CCD, Sussex County70% of 94
- Seaford CCD, Sussex County64% of 205
- Lewes CCD, Sussex County57% of 335
- Bridgeville-Greenwood CCD, Sussex County46% of 102
- Milford South CCD, Sussex County45% of 66
- Milford North CCD, Kent County34% of 41
- Millsboro CCD, Sussex County30% of 261
- Laurel-Delmar CCD, Sussex County23% of 173
- New Castle CCD, New Castle County19% of 57
- Middletown-Odessa CCD, New Castle County17% of 560
- Georgetown CCD, Sussex County13% of 151
- Kenton CCD, Kent County12% of 73
- Central Kent CCD, Kent County10% of 67
- Piedmont CCD, New Castle County10% of 93
- Dover CCD, Kent County7% of 94
- Red Lion CCD, New Castle County5% of 83
- Selbyville-Frankford CCD, Sussex County0% of 78
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.