Well water in Lafayette Parish, Louisiana
In Lafayette Parish, 4% of 112 tested well samples exceeded the EPA limit for arsenic (10 ug/L), based on public data from USGS Water Quality Portal and Louisiana LDEQ ambient ground water results (LDH Private Well Initiative).
112 individual samples from 41 wells, 1982 to 2021. Data refreshed September 9, 2026.
These are LDEQ monitoring wells sampled by aquifer on a rotation, so the shares describe the aquifer, not a survey of homeowners' wells. In that targeted sampling, 8% of 26 PFOS results in Lafayette Parish were above the EPA limit of 4 ng/L. In that targeted sampling, 0% of 26 PFOA results in Lafayette Parish were above the EPA limit of 4 ng/L.
What individual samples found
Each row summarizes every public sample for that contaminant inside Lafayette Parish. 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 | |
|---|---|---|---|---|---|---|---|
| PFOS 2020 to 2021 | 26 | 19% | 8% | 0 | 41 | 4 ng/L EPA limit | |
| Arsenic 1982 to 2021 | 112 | 100% | 4% | 1.4 | 26.9 | 10 ug/L EPA limit | |
| Lead 1982 to 2021 | 112 | 54% | 0% | 0.018 | 0.918 | 15 ug/L EPA limit | |
| Uranium 2000 to 2021 | 108 | 72% | 0% | 0.043 | 3.17 | 30 ug/L EPA limit | |
| PFOA 2020 to 2021 | 26 | 8% | 0% | 0 | 3.7 | 4 ng/L EPA limit | |
| Radon 2000 to 2013 | 23 | 100% | no limit | 380 | 2,220 | 2,000 pCi/L health guideline | |
| Manganese 2002 to 2021 | 12 | 100% | no limit | 1,025 | 1,990 | 300 ug/L health guideline | |
| Iron 2002 to 2020 | 10 | 100% | no limit | 7,155 | 8,460 | 300 ug/L nuisance level |
Sampled fewer than 10 times, too few to summarize: Copper (7), Radium (226 + 228) (6), Nitrate (5), Fluoride (1), Sodium (1).
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What this means
The contaminants most often above their limit here are pfos (8% of 26 samples) and arsenic (4% of 112 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 Lafayette Parish
- PFOS8% of 26 local samples were above the limit.
- Arsenic4% of 112 local samples were above the limit.
- Coliform bacteriaRecommended for every private well, every year.
- RadonMedian local reading is 380 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
- PFOS
- Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange
- Arsenic
- Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
- Copper
- Neutralizing filter to raise pH; Point-of-use reverse osmosis
- 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
Get your Lafayette Parish 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 Lafayette Parish.
Common questions
Is there arsenic in well water in Lafayette Parish?
Arsenic was detected in 100% of 112 public well samples in Lafayette Parish, and 4% 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 Lafayette Parish?
The median radon level across 23 public samples in Lafayette Parish was 380 pCi/L, with a high of 2,220 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Lafayette Parish?
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
- USGS Water Quality Portal: 431 samples in Lafayette Parish. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
- Louisiana LDEQ ambient ground water results (LDH Private Well Initiative): 18 samples in Lafayette Parish. Ground water sample results from the LDEQ Ambient Ground Water Monitoring Program, published by the Louisiana Department of Health Private Well Initiative. Retrieved September 9, 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.