Loading water data...
Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Real EPA measurements of nitrates for Idaho water systems — Six-Year Review compliance samples 2012–2019 (historical). Methodology
Every Idaho system with a nitrates result in EPA's data, sorted by level. Averages of 2012–2019 finished-water samples, non-detects counted as zero — historical, not today's tap.
| City | Level | Period | EPA Limit | % of Limit | Status |
|---|---|---|---|---|---|
| PocatelloGrade B | 4.63 mg/LAverage of 252 samples | 2012–2019 | 10.00 mg/L | 46.3% | Safe |
| ChubbuckGrade A | 4.52 mg/LAverage of 39 samples | 2012–2019 | 10.00 mg/L | 45.2% | Safe |
| Twin FallsGrade B | 2.51 mg/LAverage of 44 samples | 2012–2019 | 10.00 mg/L | 25.1% | Safe |
| AmmonGrade A | 2.19 mg/LAverage of 58 samples | 2012–2019 | 10.00 mg/L | 21.9% | Safe |
| KunaGrade B | 2.18 mg/LAverage of 63 samples | 2012–2019 | 10.00 mg/L | 21.8% | Safe |
| RexburgGrade A | 2.10 mg/LAverage of 58 samples | 2012–2019 | 10.00 mg/L | 21.0% | Safe |
| BlackfootGrade C | 2.08 mg/LAverage of 61 samples | 2012–2019 | 10.00 mg/L | 20.8% | Safe |
| Idaho FallsGrade A | 1.99 mg/LAverage of 67 samples | 2012–2019 | 10.00 mg/L | 19.9% | Safe |
| JeromeGrade A | 1.69 mg/LAverage of 32 samples | 2012–2019 | 10.00 mg/L | 16.9% | Safe |
| NampaGrade B | 1.50 mg/LAverage of 129 samples | 2012–2019 | 10.00 mg/L | 15.0% | Safe |
| Mountain HomeGrade C | 1.19 mg/LAverage of 68 samples | 2012–2019 | 10.00 mg/L | 11.9% | Safe |
| MeridianGrade C | 1.13 mg/LAverage of 173 samples | 2012–2019 | 10.00 mg/L | 11.3% | Safe |
| BoiseGrade B | 0.859 mg/LAverage of 568 samples | 2012–2019 | 10.00 mg/L | 8.6% | Safe |
| Post FallsGrade A | 0.860 mg/LAverage of 87 samples | 2012–2019 | 10.00 mg/L | 8.6% | Safe |
| Coeur d'AleneGrade B | 0.853 mg/LAverage of 124 samples | 2012–2019 | 10.00 mg/L | 8.5% | Safe |
| CaldwellGrade A | 0.543 mg/LAverage of 118 samples | 2012–2019 | 10.00 mg/L | 5.4% | Safe |
| Garden CityGrade B | 0.107 mg/LAverage of 75 samples | 2012–2019 | 10.00 mg/L | 1.1% | Safe |
| MoscowGrade A | 0 mg/LAverage of 38 samples | 2012–2019 | 10.00 mg/L | 0.0% | Safe |
| LewistonGrade A | 0 mg/LAverage of 24 samples | 2012–2019 | 10.00 mg/L | 0.0% | Safe |
| EagleGrade A | 0 mg/LAverage of 18 samples | 2012–2019 | 10.00 mg/L | 0.0% | Safe |
Nitrates pose the greatest risk to infants under six months of age. High nitrate levels can cause methemoglobinemia, also known as "blue baby syndrome," which reduces the blood's oxygen-carrying capacity. Pregnant women are also at risk as nitrate exposure has been linked to neural tube defects, preterm birth, and low birth weight. IMPORTANT: Boiling water does NOT remove nitrates - it concentrates them.
Runoff from fertilizer use; leaching from septic tanks; erosion of natural deposits; agricultural runoff
Based on our analysis of EPA Safe Drinking Water Information System (SDWIS) data and local water utility reports,nitrates has been detected in 20 Idaho water systems. The average level across all tested cities is 15% of the EPA Maximum Contaminant Level (MCL), with the highest detection at 46.3% of the limit.
The EPA MCL for nitrate is 10 mg/L measured as nitrogen. The EPA MCL for nitrates is 10 mg/L. This limit is set to protect public health based on available scientific evidence about the contaminant's health effects.
20 Idaho cities have nitrates detected in their water supply. All tested cities are within EPA safety limits.
Blue baby syndrome in infants, pregnancy complications, potential cancer risk. The most vulnerable groups include infants under 6 months and pregnant women.
The most effective methods for removing nitrates include Reverse Osmosis, Ion Exchange, Distillation. Look for filters certified by NSF/ANSI for nitrates reduction.
The EPA Maximum Contaminant Level (MCL) for nitrates is 10 mg/L.The EPA MCL for nitrate is 10 mg/L measured as nitrogen.
This page shows what Idaho utilities reported for nitrates. It cannot tell you what is coming out of your own tap: utility samples are taken across a whole system and averaged, levels vary by address and season, and anything picked up after the water leaves the main never appears in their report.
Home water test kitscheck your own tap before buying any filterRecommended filtration methods for nitrates removal:
Removes 83-92% of nitrates
Specifically designed for nitrate removal
Effective but energy-intensive
Paid links. We earn a commission if you buy, at no extra cost to you. Filters are matched to the removal methods listed above for nitrates.