Well water in Washington County, Nebraska
In Washington County, 16% of 207 tested well samples exceeded the EPA limit for nitrate (10 mg/L), based on public data from Nebraska Groundwater Quality Clearinghouse and USGS Water Quality Portal.
207 individual samples from 140 wells, 1967 to 2026. Data refreshed September 9, 2026.
What individual samples found
Each row summarizes every public sample for that contaminant inside Washington County. Above limit means above the EPA maximum contaminant level; where EPA has no enforceable limit, the row shows a health guideline or nuisance level instead.
| Contaminant | Samples | Detected | Above limit | Median | Highest | Limit | |
|---|---|---|---|---|---|---|---|
| Nitrate 1979 to 2024 | 207 | 62% | 16% | 0.118 | 123 | 10 mg/L EPA limit | |
| Uranium 2008 to 2026 | 153 | 99% | <1% | 0.708 | 75 | 30 ug/L EPA limit |
Sampled fewer than 10 times, too few to summarize: Fluoride (7), Arsenic (5), Radium (226 + 228) (4), Radon (8), Manganese (2), Iron (2), Sodium (2).
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What this means
The contaminants most often above their limit here are nitrate (16% of 207 samples) and uranium (<1% of 153 samples). A well next door can differ sharply from yours because bedrock fractures, well depth and plumbing all matter, so these rates describe the area, not your tap.
Manganese and Iron are widespread in local groundwater. They are mainly a staining and taste problem, but high manganese also carries a health advisory for infants.
What to test for in Washington County
- Nitrate16% of 207 local samples were above the limit.
- Uranium<1% of 153 local samples were above the limit.
- Coliform bacteriaRecommended for every private well, every year.
- RadonMedian local reading is 275 pCi/L.
- FluorideDetected in 100% of local samples.
- ManganeseDetected in 100% of local samples.
- IronDetected in 100% of local samples.
Treatment that fits the local profile
- Nitrate
- Point-of-use reverse osmosis; Anion exchange; Distillation
- Uranium
- Point-of-use reverse osmosis; Anion exchange; Whole-house anion exchange
- Fluoride
- Point-of-use reverse osmosis; Activated alumina; Distillation
- Manganese
- Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
- Iron
- Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
Get your Washington County water tested at home
A licensed local water treatment company tests your tap water in your home, walks you through the numbers, and quotes treatment only if something needs fixing. Free, about 30 minutes, no obligation. Tell us what you need and we match you with a company that serves Washington County.
Common questions
Is there arsenic in well water in Washington County?
Arsenic was detected in 100% of 5 public well samples in Washington County, and 0% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.
How high is radon in well water in Washington County?
The median radon level across 8 public samples in Washington County was 275 pCi/L, with a high of 900 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Washington County?
Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.
Sources
- Nebraska Groundwater Quality Clearinghouse: 196 samples in Washington County. Groundwater quality results compiled by the Nebraska Department of Environment and Energy, University of Nebraska and Nebraska Department of Agriculture in the Groundwater Quality Clearinghouse, contributed by Natural Resources Districts and state agencies. Retrieved September 9, 2026.
- USGS Water Quality Portal: 194 samples in Washington County. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.