Nitrate in Colorado well water
In Colorado, 40% of 5,831 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 Colorado 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 Colorado: 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 |
|---|---|---|---|---|---|
| Weld | 1,416 | 98% | 15 | 787 mg/L | |
| El Paso | 2,049 | 97% | 8.9 | 3,980 mg/L | |
| Morgan | 77 | 97% | 8.89 | 48 mg/L | |
| Arapahoe | 1,309 | 92% | 0.98 | 3,140 mg/L | |
| Douglas | 141 | 82% | 1 | 57.6 mg/L | |
| Saguache | 123 | 96% | 0.68 | 41 mg/L | |
| Boulder | 645 | 98% | 0.69 | 85 mg/L |
- La Salle-Gilcrest CCD, Weld County76% of 163
- Platteville CCD, Weld County69% of 318
- Ault CCD, Weld County57% of 46
- Greeley CCD, Weld County56% of 108
- Fountain CCD, El Paso County50% of 976
- Southeastern El Paso CCD, El Paso County50% of 206
- Kersey-Gill CCD, Weld County50% of 660
- Windsor CCD, Weld County45% of 38
- South Aurora CCD, Arapahoe County44% of 68
- Colorado Springs CCD, El Paso County43% of 794
- Keenesburg-Hudson CCD, Weld County43% of 40
- East Arapahoe CCD, Arapahoe County35% of 1,127
- Black Forest-Peyton CCD, El Paso County26% of 43
- Fort Morgan CCD, Morgan County22% of 46
- Center CCD, Saguache County17% of 89
- Southwest Arapahoe CCD, Arapahoe County17% of 114
- Longmont CCD, Boulder County16% of 140
- Parker CCD, Douglas County12% of 111
- Boulder CCD, Boulder County6% of 207
- Lafayette-Louisville CCD, Boulder County5% of 84
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.