Well water in Washington Parish, Louisiana
In Washington Parish, none of 107 tested well samples exceeded the EPA limit for fluoride, based on public data from USGS Water Quality Portal and Louisiana LDEQ ambient ground water results (LDH Private Well Initiative).
The strongest signal is lead: 42% of 12 local samples were above the limit, too few samples to carry the headline but first on the test list below.
975 test results across 12 contaminants from at least 117 wells, 1939 to 2018; chloride has the most at 404. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
These are LDEQ monitoring wells sampled by aquifer on a rotation, so the shares describe the aquifer, not a survey of homeowners' wells.
An estimated 16,979 people in Washington Parish get their drinking water from a private well, per USGS 2015 county water use. That is about 37% of residents.
Separately, the USGS national arsenic model estimates that 1% of the 16,979 people on private wells in Washington Parish draw water above 10 ug/L (the model's range is <1% to 2%), from geology and well depth rather than local tests.
What individual samples found
Each row summarizes every public sample for that contaminant inside Washington 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 | Above limit | Samples | Detected | Median | Highest | Limit |
|---|---|---|---|---|---|---|
| Lead 1977 to 2018 | 12 | 67% | 2.79 | 218 | 15 ug/L EPA limit | |
| Arsenic 1977 to 2014 | 10 | 40% | 0 | 208 | 10 ug/L EPA limit | |
| Fluoride 1939 to 2015 | 107 | 91% | 0.1 | 1.3 | 4 mg/L EPA limit | |
| Nitrate 1939 to 2013 | 93 | 94% | 0.03 | 2.2 | 10 mg/L EPA limit | |
| Copper 1977 to 2018 | 13 | 85% | 0.01 | 0.246 | 1.3 mg/L EPA limit | |
| Chloride 1939 to 2015 | no limit | 404 | 100% | 10 | 76 | 250 mg/L nuisance level |
| Iron 1945 to 2018 | no limit | 133 | 86% | 500 | 18,010 | 300 ug/L nuisance level |
| Sodium 1945 to 2015 | no limit | 101 | 100% | 16 | 110 | 20 mg/L health guideline |
| Manganese 1948 to 2018 | no limit | 96 | 84% | 40 | 1,560 | 300 ug/L health guideline |
Sampled fewer than 10 times, too few to summarize: Uranium (2), Radium (226 + 228) (2), Radon (2).
Over time
Share of samples above the limit by period. A cell needs ten samples to show; a comparison needs twenty in each period. Later periods sample fewer wells, and often the ones already known to have a problem.
| Contaminant | before 2000 | 2000s | 2010s | 2020s |
|---|---|---|---|---|
| Fluoride | 0%93 samples | n/a | 0%13 samples | n/a |
Closer than the county
See the sampled wells near your address
The same records, drawn around one point: which wells within a few miles were sampled and what they found, how deep the wells next to you were drilled, and any leaking tank or cleanup site within a mile.
Check my addressWhat this means
The contaminants most often above their limit here are lead (42% of 12 samples) and arsenic (10% of 10 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.
Chloride, Iron, and Manganese 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 Parish
- 1Lead42% of 12 local samples were above the limit.
- 2Arsenic10% of 10 local samples were above the limit.
- 3Coliform bacteriaRecommended for every private well, every year.
- 4RadonMedian local reading is 216 pCi/L.
- 5NitrateRecommended for every private well, especially near farms or septic systems.
- 6ChlorideDetected in 100% of local samples.
- 7FluorideDetected in 91% of local samples.
Test your Washington Parish well for lead, arsenic and coliform bacteria
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
Just want bacteria checked first? Tap Score coliform and E. coli test, $99. Coliform and E. coli are the tests every well needs every year.
Want a quick look before paying for a lab? Home well water test strips on Amazon check hardness, iron, pH and nitrate in minutes. They are a screen, not a result: arsenic, bacteria, uranium and PFAS need a certified lab.
Affiliate links: the merchant pays us a commission and the price is the same for you. It does not change what the data above says. As an Amazon Associate we earn from qualifying purchases.
Where to get a well tested in Louisiana: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Washington Parish numbers, $29. Every line explained, ranked by what matters, with the fix for each.
The rock under Washington Parish
Coastal lowlands aquifer system
Semiconsolidated sand. Coastal plain sands like these give steady yields at moderate depth. Salt water and sodium are the usual issues near the coast, and nitrate where the water table is shallow; arsenic and radon from bedrock are less common.
Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the parish centroid. A single well can sit in a different unit, especially near a boundary.
Official help in Louisiana
Two places to start that are not selling anything: the state program that answers private well questions, and its list of labs certified to run drinking water tests. A certified lab is the difference between a result you can act on and a number.
- Private Well Initiative, Louisiana Department of Health
- Laboratory Certification, Louisiana Department of Health
Treatment that fits the local profile
Lead
Point-of-use reverse osmosis; Certified lead-removal carbon filter; Neutralizing filter to raise pH and stop leaching
Arsenic
Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
Iron
Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
Manganese
Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
Systems we would look at first
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For lead
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
For lead
Acid neutralizing filter
whole-house, at the point of entry, about $1,200
Raises pH so plumbing stops leaching lead and copper.
For lead
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.
For arsenic
Whole-house arsenic and uranium filter
whole-house, at the point of entry, about $2,500
Adsorptive iron-based media; sized to your well yield.
For iron
Iron and manganese oxidizing filter
whole-house, at the point of entry, about $1,800
Air-injection or greensand media; fixes staining at the source.
Free, no obligation
Get on the list for a free in-home water test in Washington Parish
No water treatment company serves Washington Parish through Well Water Nerd yet. We are signing licensed companies on county by county: they test at your tap for free, walk you through the numbers, and quote treatment only if something needs fixing. Leave your details and you are first in line. Nothing is shared until a company joins for Washington Parish, and you get an email naming it first.
Common questions
Is there arsenic in well water in Washington Parish?
Arsenic was detected in 40% of 10 public well samples in Washington Parish, and 10% 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 often should I test a private well in Washington 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.
Parishes near Washington Parish
Closest first. Groundwater does not stop at a line on a map, so the next parish over is a fair second opinion.
Want the numbers themselves? Download the Louisiana dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 939 samples in Washington 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): 36 samples in Washington 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.
- USGS national arsenic model (Ayotte 2017): estimated share of 16,979 people on private wells in Washington Parish above 10 ug/L of arsenic, from geology, well depth and land use. County estimates of domestic well users with arsenic above 10 ug/L from the USGS national logistic regression model (Ayotte, Medalie and Qi, 2017), with private well population from the USGS 2015 county water-use compilation (Dieter and others, 2018). Retrieved September 15, 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.