Fort Hall nitrate priority area
Idaho DEQ sampled 17 wells here when designating this area. 10 of them (58%) read above the EPA limit of 10 mg/L, with a highest reading of 23.6 mg/L. That describes those wells — not yours.
- Wells sampled
- 17
- the denominator for everything here
- Above 10 mg/L
- 10 (58%)
- ranked 1 of 35 Idaho areas
- Highest reading
- 23.6 mg/L
- Median reading
- 11 mg/L
Small sample. This area's figures come from 17 wells. One unusual reading moves a percentage a long way at that size, so treat the share above the limit as a rough signal rather than a measurement.
The full picture
| Area size | 17,277 acres (27 sq mi) |
|---|---|
| Population inside | 1,158 |
| Above 10 mg/L | 10 of 17 (58%) |
| Above 5 mg/L | 14 of 17 |
| Above 2 mg/L | 16 of 17 |
| Trend | DEQ recorded insufficient data to establish a trend |
| DEQ regional office | Pocatello Regional Office |
Idaho Department of Environmental Quality, published through IDWR, retrieved 2026-10-19. Readings above 2 and 5 mg/L are included because the EPA limit is a regulatory threshold, not a line where water becomes unsafe — a rising figure well under 10 still tells you something about the aquifer.
What this designation does and does not tell you
DEQ draws these boundaries from the samples it holds. The figures above describe 17 specific wells, sampled at specific times, by whichever agency collected them. They are good evidence about the aquifer and no evidence at all about one address.
Being inside this area does not mean a well here is contaminated. Being outside it does not mean a well is clean — it may only mean nobody has sampled nearby. Nitrate is colourless, odourless and tasteless, so there is no way to notice it without a test.
Why it matters more for some households
The EPA limit of 10 mg/L was set with infants in mind. Nitrate interferes with how blood carries oxygen, and the risk is concentrated in babies under six months, which is why guidance singles out pregnancy and bottle-feeding.
Boiling does not help — it concentrates nitrate rather than removing it. That is the most common and most consequential misunderstanding about this contaminant.
What to do
- Test the well you will actually drink from, through a certified drinking-water lab.
- If there is an infant in the house or someone is pregnant, do it before you rely on the water rather than after.
- Ask the seller for previous results and check the date. A reading from a decade ago describes a decade ago.
- Contact the Pocatello Regional Office for what is known about this specific area.
Nitrate is treatable — reverse osmosis, ion exchange and distillation all address it. Which is appropriate depends on the reading and the household, and that is a question for a water treatment professional once you have a result in hand.
Check a specific parcel
See whether a point falls inside this area, along with the well records the state holds nearby — depth, depth to water and yield.