privatewelldata / States / New York / Nitrate
Nitrate in well water in New York
5% of 6,236 sampled wells in New York had nitrate above the EPA limit of 10 mg/L (as nitrogen) (latest result per well, 60 counties, samples 1919–2023). The highest county share was Kings County: 31% of 93 wells. Data updated 2026-10-18.
of sampled wells above 10 mg/L (as nitrogen)
wells with a result
counties with data
counties where 1 in 4+ wells were above
Nitrate in wells most often comes from fertilizer, manure and septic systems, so shallow wells near fields or septic fields are more exposed, and levels can change with the seasons. Only a lab test shows it. Federal limits apply to public water systems; a private well is the owner's responsibility to test (EPA).
% of sampled wells above the EPA limit (latest result per well; counties with 10+ wells). Source: USGS/EPA Water Quality Portal, 2026-10-18 · privatewelldata.com
Nitrate by county in New York
| County | Above 10 mg/L (as nitrogen) | Median | 90th pct. | Years |
|---|---|---|---|---|
| Kings County | 31% of 93 | 7.025 mg/L as N | 16.49 | 1967–2013 |
| Montgomery County | 9% of 57 | 0.045 mg/L as N | 7.409 | 1967–2021 |
| Nassau County | 9% of 1,663 | 3 mg/L as N | 9.8 | 1934–2022 |
| Queens County | 8% of 194 | 4.33 mg/L as N | 9.646 | 1970–2018 |
| Suffolk County | 5% of 1,659 | 0.86 mg/L as N | 7.6 | 1919–2023 |
| Niagara County | 5% of 22 | 0.065 mg/L as N | 2.711 | 1948–2011 |
| Richmond County | 4% of 23 | 1.74 mg/L as N | 4.044 | 2005–2012 |
| Washington County | 4% of 23 | 0.203 mg/L as N | 1.11 | 1971–2023 |
| Genesee County | 4% of 26 | 0.387 mg/L as N | 2.5 | 1963–2021 |
| Livingston County | 3% of 30 | 0.041 mg/L as N | 5.647 | 1964–2020 |
| St. Lawrence County | 3% of 78 | 0.194 mg/L as N | 1.56 | 1955–2020 |
| Schenectady County | 2% of 43 | 0.22 mg/L as N | 1.1 | 1947–2021 |
| Erie County | 2% of 101 | 0.12 mg/L as N | 7 | 1951–2021 |
| Oswego County | 2% of 59 | 0.11 mg/L as N | 2.9 | 1964–2022 |
| Albany County | 2% of 66 | 0.09 mg/L as N | 3.3 | 1947–2021 |
| Saratoga County | 1% of 72 | 0.042 mg/L as N | 2.9 | 1951–2023 |
| Oneida County | 1% of 75 | 0.023 mg/L as N | 2.507 | 1952–2022 |
| Steuben County | 1% of 76 | 0.13 mg/L as N | 2.54 | 1953–2020 |
| Cortland County | 1% of 112 | 2.95 mg/L as N | 6.4 | 1952–2019 |
| Westchester County | 0% of 119 | 0.333 mg/L as N | 2.4 | 1971–2018 |
| Orange County | 0% of 110 | 0.074 mg/L as N | 1.62 | 1952–2020 |
| Tompkins County | 0% of 93 | 0 mg/L as N | 0.732 | 1965–2023 |
| Cattaraugus County | 0% of 78 | 0.302 mg/L as N | 2.711 | 1962–2021 |
| Ulster County | 0% of 69 | 0 mg/L as N | 0.547 | 1966–2021 |
| Allegany County | 0% of 65 | 0.023 mg/L as N | 0.41 | 1965–2021 |
| Broome County | 0% of 63 | 0.05 mg/L as N | 1.17 | 1952–2023 |
| Jefferson County | 0% of 61 | 0.161 mg/L as N | 2.3 | 1951–2020 |
| Monroe County | 0% of 60 | 0.026 mg/L as N | 2.74 | 1964–2022 |
| Clinton County | 0% of 59 | 0.023 mg/L as N | 0.481 | 1962–2019 |
| Herkimer County | 0% of 59 | 0.384 mg/L as N | 2.01 | 1966–2023 |
| Essex County | 0% of 53 | 0.113 mg/L as N | 1.161 | 1962–2022 |
| Onondaga County | 0% of 53 | 0.1 mg/L as N | 2.824 | 1953–2022 |
| Chautauqua County | 0% of 52 | 0.226 mg/L as N | 4.52 | 1952–2021 |
| Delaware County | 0% of 48 | 0.661 mg/L as N | 2.94 | 1949–2020 |
| Ontario County | 0% of 43 | 0.09 mg/L as N | 3.48 | 1952–2022 |
| Chemung County | 0% of 40 | 0.474 mg/L as N | 2.711 | 1953–2018 |
| Dutchess County | 0% of 39 | 0.7 mg/L as N | 2.7 | 1949–2018 |
| Greene County | 0% of 39 | 0.051 mg/L as N | 0.5 | 1972–2021 |
| Wayne County | 0% of 37 | 0.05 mg/L as N | 2.1 | 1965–2022 |
| Sullivan County | 0% of 36 | 0.296 mg/L as N | 1.331 | 1957–2020 |
| Lewis County | 0% of 34 | 0.14 mg/L as N | 1.4 | 1961–2020 |
| Warren County | 0% of 33 | 0.12 mg/L as N | 1.29 | 1966–2022 |
| Otsego County | 0% of 30 | 0.14 mg/L as N | 2.17 | 1965–2019 |
| Putnam County | 0% of 30 | 0.322 mg/L as N | 4.48 | 1972–2018 |
| Wyoming County | 0% of 29 | 0.05 mg/L as N | 5.57 | 1963–2021 |
| Cayuga County | 0% of 28 | 0.195 mg/L as N | 3 | 1964–2022 |
| Seneca County | 0% of 27 | 0.05 mg/L as N | 2.711 | 1948–2022 |
| Madison County | 0% of 26 | 0.709 mg/L as N | 2.7 | 1961–2022 |
| New York County | 0% of 26 | 0 mg/L as N | 4.42 | 1973–2011 |
| Tioga County | 0% of 26 | 0.048 mg/L as N | 3.3 | 1967–2019 |
| Chenango County | 0% of 24 | 0 mg/L as N | 1.89 | 1965–2019 |
| Hamilton County | 0% of 24 | 0.456 mg/L as N | 1.491 | 1967–2022 |
| Yates County | 0% of 23 | 0.05 mg/L as N | 0.321 | 1966–2022 |
| Franklin County | 0% of 22 | 0.037 mg/L as N | 0.49 | 1962–2020 |
| Schoharie County | 0% of 21 | 0 mg/L as N | 0.48 | 1967–2021 |
| Columbia County | 0% of 20 | 0.032 mg/L as N | 0.9 | 1971–2018 |
| Rensselaer County | 0% of 18 | 0.123 mg/L as N | 1.071 | 1973–2022 |
| Schuyler County | 0% of 17 | 0.05 mg/L as N | 0.76 | 1966–2022 |
| Fulton County | 0% of 15 | 0.187 mg/L as N | 1.312 | 1971–2022 |
| Rockland County | 0% of 15 | 0.7 mg/L as N | 1.29 | 1957–2018 |
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Download this table (CSV) · public-domain source data: Water Quality Portal (USGS, EPA, NWQMC). How we calculate these numbers.
How New York compares
Share of sampled wells above the EPA nitrate limit in each state we cover (states with 100+ wells).
| # | State | Above 10 mg/L (as nitrogen) |
|---|---|---|
| 1 | California | 10% of 16,344 |
| 2 | Pennsylvania | 8% of 6,478 |
| 3 | Minnesota | 6% of 7,259 |
| 4 | North Carolina | 5% of 1,964 |
| 5 | New York | 5% of 6,236 |
| 6 | Massachusetts | 4% of 2,556 |
| 7 | New Jersey | 4% of 3,915 |
| 8 | Wisconsin | 4% of 3,666 |
| 9 | Virginia | 3% of 1,394 |
| 10 | Maine | 2% of 726 |
| 11 | Michigan | 2% of 1,970 |
| 12 | Ohio | 1% of 1,239 |
| 13 | New Hampshire | 0% of 1,685 |
Where to test: official lab list for New York
About this data
- Each well counts once, using its latest nitrate result in the Water Quality Portal (siteType = Well), downloaded 2026-10-18.
- Results reported as "not detected" count as below the limit. Results far outside the plausible range are withheld for review, not shown.
- Sampled wells include monitoring and research wells, not only household wells, and are not a random sample, so the share is a guide to local risk, not a rate for all homes.
- The limit is the EPA maximum contaminant level for public water systems (EPA).
Questions
Is nitrate common in New York well water?
In our data, 295 of 6,236 sampled wells in New York (5%) had a latest nitrate result above the EPA limit of 10 mg/L (as nitrogen), across 60 counties. That ranks New York 5 of 13 states we cover for this share.
Which New York counties have the most wells above the nitrate limit?
Among counties with at least 10 sampled wells: Kings County (31%, 29 of 93 wells); Montgomery County (9%, 5 of 57 wells); Nassau County (9%, 142 of 1663 wells).
Does this tell me whether my well is safe?
No. These are past results from wells sampled by USGS, EPA and state programs, including monitoring wells, and levels differ from well to well. The only way to know your water is to test your own well at a certified lab.
How do I test my well for nitrate in New York?
Order a nitrate test from a lab on New York's official certified-lab list (linked on this page) and ask for its bottles and sampling instructions. Our test helper suggests what else to test for at the same time.
What should I do if my nitrate result is above 10 mg/L (as nitrogen)?
Retest to confirm, use another water source for drinking and cooking while you sort it out, and look at certified treatment options. Our guide walks through each step with sources.