Well water in Westchester County, New York
1in4
Testing strongly recommended
tested well samples in Westchester County exceeded the EPA limit for lead (15 ug/L), based on public data from USGS Water Quality Portal.
805 test results across 11 contaminants from at least 113 wells, 1971 to 2018; manganese has the most at 154. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 42,961 people in Westchester County get their drinking water from a private well, per USGS 2015 county water use. That is about 4% of residents.
Separately, the USGS national arsenic model estimates that 1% of the 42,961 people on private wells in Westchester County 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 Westchester 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 | Above limit | Samples | Detected | Median | Highest | Limit |
|---|---|---|---|---|---|---|
| Lead 1971 to 2018 | 72 | 85% | 1.17 | 301 | 15 ug/L EPA limit | |
| Arsenic 1971 to 2018 | 73 | 86% | 1.1 | 32.3 | 10 ug/L EPA limit | |
| Fluoride 1971 to 2018 | 99 | 98% | 0.15 | 1.6 | 4 mg/L EPA limit | |
| Copper 1971 to 2018 | 72 | 97% | 0.012 | 0.74 | 1.3 mg/L EPA limit | |
| Uranium 1995 to 2018 | 11 | 91% | 0.513 | 2.33 | 30 ug/L EPA limit | |
| Manganese 1971 to 2018 | no limit | 154 | 81% | 17.1 | 24,600 | 300 ug/L health guideline |
| Iron 1971 to 2018 | no limit | 154 | 80% | 20.5 | 269,000 | 300 ug/L nuisance level |
| Chloride 1971 to 2018 | no limit | 153 | 99% | 24.8 | 1,630 | 250 mg/L nuisance level |
Sampled fewer than 10 times, too few to summarize: E. coli (7), Radium (226 + 228) (1), Radon (9).
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%42 samples | 0%16 samples | 0%41 samples | n/a |
| Arsenic | 0%16 samples | 6%16 samples | 7%41 samples | n/a |
| Lead | 0%15 samples | 25%16 samples | 32%41 samples | n/a |
| Copper | 0%15 samples | 0%16 samples | 0%41 samples | n/a |
Fluoride has held within a few points between the two most recent periods with enough samples.
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 (24% of 72 samples) and arsenic (5% of 73 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, Iron, and Chloride 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 Westchester County
- 1Lead24% of 72 local samples were above the limit.
- 2Arsenic5% of 73 local samples were above the limit.
- 3Coliform bacteriaRecommended for every private well, every year.
- 4RadonMedian local reading is 700 pCi/L.
- 5NitrateRecommended for every private well, especially near farms or septic systems.
- 6ChlorideDetected in 99% of local samples.
- 7FluorideDetected in 98% of local samples.
- 8Volatile organic compounds (VOCs)111 hazardous waste sites on record locally.
- 9Metals panel111 hazardous waste sites on record locally.
Test your Westchester County 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 New York: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Westchester County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
Wells in Westchester County
1,012 domestic wells in Westchester County are on record with the state. the typical well is 465 feet deep (one in ten goes past 746 feet).
Find your own well's report
The state keeps the driller's report for most wells drilled since 1984. It tells you how deep your well is, where bedrock starts, and how much water it makes, which decides what treatment can work.
- Open NYSDEC water well completion reports and choose Water Well.
- The report lists depth, depth to bedrock, cased depth, yield and the driller.
Drillers have filed reports with the state since April 2000; a well drilled before then usually has no record.
The rock under Westchester County
Not a principal aquifer
The USGS map places this area outside any principal aquifer, which usually means wells here draw from fractured bedrock or thin local deposits rather than a large regional aquifer. Bedrock wells of that kind are where arsenic, radon and uranium turn up, and yields vary from well to well.
Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the county centroid. A single well can sit in a different unit, especially near a boundary.
Official help in New York
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 Wells, NYSDOH
- Environmental Laboratory Approval Program, NYSDOH
Contamination sources on record in Westchester County
NYSDEC remediation sites records 111 hazardous waste sites in Westchester County, among 367 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.
- 111
- hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 256
- other remediation projects
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
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
Systems we would look at first
Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.
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 manganese
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 Westchester County
No water treatment company serves Westchester County 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 Westchester County, and you get an email naming it first.
Common questions
How deep are wells in Westchester County?
The typical domestic well in Westchester County is 465 feet deep, based on 1,012 wells reported to the state. One in ten is deeper than 746 feet.
Is there arsenic in well water in Westchester County?
Arsenic was detected in 86% of 73 public well samples in Westchester County, and 5% 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 Westchester 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.
Towns in Westchester County
24 towns have fewer than 30 public samples and are included in the Westchester County totals above rather than shown separately: Bedford, Cortlandt, Eastchester, Greenburgh, Harrison, Lewisboro, Mamaroneck, Mount Kisco, Mount Pleasant, Mount Vernon, New Castle, New Rochelle, North Castle, North Salem, Ossining, Peekskill, Pelham, Pound Ridge, Rye, Rye, Scarsdale, Somers, White Plains, Yorktown.
Counties near Westchester County
Closest first. Groundwater does not stop at a line on a map, so the next county over is a fair second opinion.
Want the numbers themselves? Download the New York dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 805 samples in Westchester 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.
- USGS national arsenic model (Ayotte 2017): estimated share of 42,961 people on private wells in Westchester County 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.
- NYSDEC water well completion reports: 1,216 well records in Westchester County, 1,012 domestic. Water well completion reports filed with the New York State Department of Environmental Conservation Water Well Contractor Program since 2000. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 16, 2026.
- NYSDEC remediation sites: 367 regulated sites located in Westchester County. State Superfund, brownfield, voluntary cleanup, RCRA and spill remediation sites from the New York State Department of Environmental Conservation Environmental Remediation Sites database. Retrieved September 16, 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.