Tap & Air

Private wells

New York well water: who's on a well and what to test for

An estimated 1,784,100 people in 876,800 homes, about 10.3% of New York homes, below the national 14.6%. Estimates are from EPA's Water Source 2020 model.

People on private wells

1,784,100

Homes on wells

10.3%

Est. above arsenic limit

66,300

Albany County: about 7% of homes on private wellsAllegany County: about 61% of homes on private wellsBronx County: about 0% of homes on private wellsBroome County: about 22% of homes on private wellsCattaraugus County: about 48% of homes on private wellsCayuga County: about 39% of homes on private wellsChautauqua County: about 33% of homes on private wellsChemung County: about 25% of homes on private wellsChenango County: about 63% of homes on private wellsClinton County: about 46% of homes on private wellsColumbia County: about 63% of homes on private wellsCortland County: about 39% of homes on private wellsDelaware County: about 68% of homes on private wellsDutchess County: about 33% of homes on private wellsErie County: about 3% of homes on private wellsEssex County: about 42% of homes on private wellsFranklin County: about 58% of homes on private wellsFulton County: about 46% of homes on private wellsGenesee County: about 33% of homes on private wellsGreene County: about 67% of homes on private wellsHamilton County: about 69% of homes on private wellsHerkimer County: about 43% of homes on private wellsJefferson County: about 38% of homes on private wellsKings County: about 0% of homes on private wellsLewis County: about 69% of homes on private wellsLivingston County: about 38% of homes on private wellsMadison County: about 38% of homes on private wellsMonroe County: about 1% of homes on private wellsMontgomery County: about 37% of homes on private wellsNassau County: about 0% of homes on private wellsNew York County: about 0% of homes on private wellsNiagara County: about 1% of homes on private wellsOneida County: about 22% of homes on private wellsOnondaga County: about 6% of homes on private wellsOntario County: about 22% of homes on private wellsOrange County: about 27% of homes on private wellsOrleans County: about 48% of homes on private wellsOswego County: about 41% of homes on private wellsOtsego County: about 59% of homes on private wellsPutnam County: about 54% of homes on private wellsQueens County: about 0% of homes on private wellsRensselaer County: about 28% of homes on private wellsRichmond County: about 0% of homes on private wellsRockland County: about 0% of homes on private wellsSt. Lawrence County: about 58% of homes on private wellsSaratoga County: about 24% of homes on private wellsSchenectady County: about 6% of homes on private wellsSchoharie County: about 72% of homes on private wellsSchuyler County: about 71% of homes on private wellsSeneca County: about 40% of homes on private wellsSteuben County: about 50% of homes on private wellsSuffolk County: about 2% of homes on private wellsSullivan County: about 59% of homes on private wellsTioga County: about 58% of homes on private wellsTompkins County: about 34% of homes on private wellsUlster County: about 54% of homes on private wellsWarren County: about 35% of homes on private wellsWashington County: about 59% of homes on private wellsWayne County: about 22% of homes on private wellsWestchester County: about 4% of homes on private wellsWyoming County: about 52% of homes on private wellsYates County: about 64% of homes on private wells
Homes on private wellsUnder 5%5-15%15-30%30-50%50% or more

Every New York county

Sorted by people on private wells. Arsenic and nitrate are modeled for typical wells in the county, not measured at yours; depth is the median of domestic well records.

Orange County108,70027%n/an/a278 ft
Dutchess County97,90033%n/an/a300 ft
Ulster County90,90054%n/an/a248 ft
St. Lawrence County56,80058%n/an/a117 ft
Saratoga County56,80024%n/an/a178 ft
Putnam County53,20054%n/an/a305 ft
Oneida County51,50022%n/an/a95 ft
Oswego County47,70041%n/an/a74 ft
Rensselaer County47,20028%n/an/a300 ft
Steuben County46,50050%n/an/a120 ft
Westchester County45,5004%n/an/a345 ft
Broome County44,30022%n/an/a165 ft
Chautauqua County44,00033%n/an/a80 ft
Sullivan County43,30059%n/an/a300 ft
Jefferson County41,40038%n/an/a103 ft
Cattaraugus County37,90048%n/an/a100 ft
Columbia County37,50063%n/an/a310 ft
Clinton County35,60046%n/an/a157 ft
Tompkins County34,60034%n/an/a140 ft
Washington County34,00059%n/an/a320 ft
Erie County33,2003%n/an/a70 ft
Otsego County32,20059%n/an/a163 ft
Cayuga County31,70039%n/an/a120 ft
Greene County29,90067%n/an/a250 ft
Chenango County29,30063%n/an/a180 ft
Tioga County28,40058%n/an/a120 ft
Onondaga County28,4006%n/an/a140 ft
Delaware County27,40068%n/an/a248 ft
Madison County25,40038%n/an/a117 ft
Ontario County25,30022%n/an/a100 ft
Franklin County24,50058%n/an/a150 ft
Allegany County24,50061%n/an/a105 ft
Herkimer County23,90043%n/an/a160 ft
Livingston County23,50038%n/an/a106 ft
Fulton County23,10046%n/an/a200 ft
Chemung County21,80025%n/an/a127 ft
Wyoming County21,60052%n/an/a80 ft
Albany County21,0007%n/an/a239 ft
Montgomery County20,50037%n/an/a185 ft
Genesee County20,50033%n/an/a55 ft
Schoharie County20,40072%n/an/a235 ft
Orleans County19,70048%n/an/a43 ft
Wayne County19,50022%n/an/a79 ft
Suffolk County18,8002%n/an/a65 ft
Cortland County18,20039%n/an/a160 ft
Warren County17,60035%n/an/a280 ft
Lewis County17,40069%n/an/a144 ft
Yates County15,30064%n/an/a110 ft
Essex County15,00042%n/an/a300 ft
Seneca County14,00040%n/an/a100 ft
Schuyler County13,30071%n/an/a100 ft
Schenectady County9,7006%n/an/a239 ft
Monroe County5,7001%n/an/a63 ft
Hamilton County3,30069%n/an/a280 ft
Niagara County3,1001%n/an/a55 ft
Nassau County1,1000%n/an/a135 ft
Rockland County3200%n/an/a224 ft
Bronx County00%n/an/an/a
Kings County00%n/an/an/a
New York County00%n/an/an/a
Queens County00%n/an/an/a
Richmond County00%n/an/an/a

Shading: red is among the highest counties nationally, amber the middle, green the lower range. Click a column to sort.

Test first, then treat what the test finds

We may earn a commission from links below, at no cost to you. Picks follow the testing order, not who pays. How we make money.

1. Certified lab well test

Start here, every year

A mail-in kit analyzed by a certified lab measures bacteria, nitrate, arsenic, metals and more. Test strips cannot measure arsenic or uranium reliably.

Mail-in certified lab well water test$$

2. Sediment pre-filter

Sand, silt or cloudy water

A 5-micron cartridge after the pressure tank catches sand, silt and rust before they reach fixtures or other filters. Cartridges are cheap and swap every few months.

5-micron whole-house sediment filter$

3. Iron and sulfur filter

Orange stains or rotten-egg smell

Air-injection or oxidizing-media filters remove orange staining and rotten-egg smell. Size one from a lab result for iron, manganese and hydrogen sulfide.

Air-injection iron and sulfur filter$$$

4. UV disinfection system

Coliform bacteria in a test

Inactivates bacteria and viruses; usually for private wells or after boil notices.

12 GPM whole-house UV purifier$$$

5. Under-sink reverse osmosis

Arsenic, nitrate or uranium in a test

The most thorough option for drinking water: PFAS, lead, nitrate, arsenic and more. Look for NSF/ANSI 58.

Waterdrop G3P600 tankless RO$$$ iSpring RCC7AK reverse osmosis$$

6. Whole-house well filter

Several problems at once

Multi-stage sediment and carbon for every tap. Add UV if bacteria shows up, and choose stages from your lab results, not a guess.

Waterdrop WHF21 2-stage whole-house filter$$
Get free well water treatment quotes

Questions

Which New York counties rely most on wells?+

By share of homes: Schoharie County (72%), Schuyler County (71%), Lewis County (69%), Hamilton County (69%), Delaware County (68%). By number of people: Orange County (108,700), Dutchess County (97,900), Ulster County (90,900).

Is arsenic a problem in New York wells?+

USGS estimates about 66,300 New York well users have water above the 10 microgram per liter arsenic limit that applies to public systems. Arsenic has no taste or smell, so only a lab test finds it.

Do I have to test my well when I sell a house in New York?+

We could not confirm a statewide rule for New York. Check with your county health department. Buyers can still make a lab test a condition of the offer.

How often should I test my well?+

No federal law covers private wells. EPA's drinking water limits apply to public water systems, so testing and treating a private well is up to the owner. EPA and CDC recommend testing at least once a year for coliform bacteria, nitrate, pH and total dissolved solids, and testing for arsenic, uranium, radon and other local concerns based on where you live.

Well-user counts, arsenic and nitrate figures are each a modeled estimate built from national datasets, not a count of tested wells, and well depths summarize drilling records rather than every well. Your own well can be very different from the county average, which is why the only answer for your home is a lab test. Sources: EPA Office of Research and Development, Water Source 2020 (private well estimates by census block); CDC Environmental Public Health Tracking, Well Water Index (from USGS nitrate and arsenic models); USGS, county-level domestic well population with arsenic above 10 micrograms per liter (Ayotte and others, 2017); USGS Synthesized Domestic Well Database for the Conterminous United States (SynDWell-US), McCarthy and others, 2025 (depth, where a county has 30+ usable records).