Nitrate in Montana well water
In Montana, 11% of 8,286 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 Montana 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 Montana: 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 |
|---|---|---|---|---|---|
| Valley | 475 | 96% | 9.95 | 486 mg/L | |
| Roosevelt | 458 | 86% | 7.3 | 586 mg/L | |
| Daniels | 117 | 94% | 5.1 | 138 mg/L | |
| Chouteau | 63 | 100% | 2.7 | 1,770 mg/L | |
| Stillwater | 60 | 98% | 1.5 | 280 mg/L | |
| Cascade | 85 | 95% | 2.47 | 575 mg/L | |
| Teton | 152 | 74% | 3 | 708 mg/L | |
| Liberty | 47 | 100% | 0.22 | 500 mg/L | |
| Hill | 49 | 100% | 0.7 | 89 mg/L | |
| Dawson | 57 | 84% | 0.3 | 146 mg/L | |
| McCone | 167 | 90% | 1.5 | 115 mg/L | |
| Toole | 33 | 94% | 0.4 | 240 mg/L | |
| Treasure | 42 | 98% | 0.475 | 31 mg/L | |
| Phillips | 70 | 96% | 0.9 | 89 mg/L | |
| Garfield | 40 | 98% | 2.7 | 21 mg/L |
- Geraldine CCD, Chouteau County55% of 31
- Fort Peck Reservation CCD, Valley County54% of 410
- Fort Peck Reservation CCD, Daniels County49% of 76
- North Stillwater CCD, Stillwater County45% of 44
- Fort Peck Reservation CCD, Roosevelt County45% of 440
- Denton CCD, Fergus County31% of 32
- Scobey CCD, Daniels County29% of 41
- Opheim CCD, Valley County22% of 32
- Richey CCD, Dawson County21% of 39
- Fairfield CCD, Teton County17% of 134
- Malta CCD, Phillips County14% of 35
- North McCone CCD, McCone County13% of 45
- Circle CCD, McCone County12% of 122
- Melstone CCD, Musselshell County12% of 33
- Lambert CCD, Richland County12% of 33
- Chester CCD, Liberty County11% of 36
- Manhattan CCD, Gallatin County9% of 34
- Cut Bank CCD, Glacier County9% of 35
- Stanford CCD, Judith Basin County8% of 53
- Lewistown CCD, Fergus County7% of 87
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.