USCanada

privatewelldata / Counties

Well water by county: New York

Across 58 counties in New York, 55 of 2654 sampled wells (2%) were above the arsenic limit and 206 of 4555 (5%) above the nitrate limit. Updated 2026-10-18. Source: Water Quality Portal (USGS, EPA, NWQMC), siteType=Well.

Share of sampled wells whose latest result is above the EPA limit (arsenic 10 µg/L, nitrate 10 mg/L as N).

Share of sampled wells above the limit, by county (% of wells). Source: USGS/EPA Water Quality Portal · privatewelldata.com
CountyArsenic > 10 µg/LNitrate > 10 mg/L
Albany County0% of 272% of 66
Allegany County19% of 320% of 65
Broome County5% of 410% of 63
Cattaraugus County0% of 330% of 78
Cayuga County0% of 170% of 28
Chautauqua County3% of 290% of 52
Chemung County0% of 100% of 40
Chenango County5% of 210% of 24
Clinton County0% of 260% of 59
Columbia County0% of 140% of 20
Cortland County0% of 271% of 112
Delaware County0% of 370% of 48
Dutchess County0% of 360% of 39
Erie County3% of 792% of 101
Essex County0% of 390% of 53
Franklin County0% of 180% of 22
Fulton County0% of 150% of 15
Genesee County0% of 194% of 26
Greene County9% of 110% of 39
Hamilton County0% of 170% of 24
Herkimer County0% of 250% of 59
Jefferson County0% of 340% of 61
Kings County0% of 7331% of 93
Lewis County0% of 240% of 34
Livingston County5% of 213% of 30
Madison County0% of 220% of 26
Monroe County18% of 280% of 60
Montgomery County0% of 159% of 57
Nassau County0% of 8889% of 1,663
New York County0% of 260% of 26
Oneida County8% of 381% of 75
Onondaga County4% of 270% of 53
Ontario County0% of 200% of 43
Orange County0% of 480% of 110
Oswego County17% of 422% of 59
Otsego County0% of 180% of 30
Putnam County0% of 230% of 30
Queens County0% of 1538% of 194
Rensselaer County7% of 150% of 18
Richmond County0% of 234% of 23
Rockland County–0% of 15
Saratoga County6% of 691% of 72
Schenectady County0% of 322% of 43
Schoharie County0% of 190% of 21
Schuyler County–0% of 17
Seneca County0% of 100% of 27
St. Lawrence County0% of 483% of 78
Steuben County5% of 211% of 76
Sullivan County3% of 300% of 36
Tioga County15% of 200% of 26
Tompkins County4% of 720% of 93
Ulster County6% of 680% of 69
Warren County0% of 300% of 33
Washington County0% of 234% of 23
Wayne County6% of 170% of 37
Westchester County6% of 660% of 119
Wyoming County0% of 180% of 29
Yates County–0% of 23