Some of these decisions are not final. 2,126 of these 2,231 records carry a verdict New York decided in its 2022 Integrated Report, which carries an interim EPA action, so they can change before EPA takes final action on the cycle. They are counted in every figure on this page.
Some of these decisions are EPA's. 73 of these 2,231 records carry at least one designated-use verdict or impairment listing EPA filed rather than New York; on those, the determination is EPA's rather than New York's. They are counted in every figure on this page, and each record page names which.
State water-quality picture · #5 by reported lake-type waterbodies
New York lakes and reservoirs
Every figure on this page is computed from the assessment decisions New York reported to the U.S. Environmental Protection Agency under Clean Water Act sections 303(d) and 305(b) (reporting cycles 2016–2022), plus daily water-level observations from the U.S. Geological Survey.
- 2,231
- Reported waterbodies
- 563
- Not supporting a use
- Not reported
- Fish use assessments
- 16
- Gauged lakes
New York in one line
2,231 lake-type waterbodies in New York are reported to EPA ATTAINS across reporting cycles 2016–2022: 563 assessed as not supporting at least one designated use, 79 fully supporting, and 1,589 without a definitive overall verdict. The most-listed impairment cause is pH, on 211 waterbodies.
- 2,231
- reported waterbodies
- 563
- not supporting a use
- 79
- fully supporting
- 88%
- of definitive verdicts impaired
An unassessed waterbody is neither confirmed clean nor confirmed impaired; states assess on multi-year cycles.
New York's large register still carries a heavy not-supporting share
Among the largest third of state lake-type registers (2,231 units), New York also sits in the upper third for ruled not-supporting share (88%). The size and the load move together here, not every large inventory does.
Data updated 2026-08-17
According to the U.S. Environmental Protection Agency's ATTAINS program, New York reported 2,231 lake-type waterbodies in New York in the August 2026 extract. See our methodology for filer attribution and multi-year reporting cycles.
How New York's large inventory splits across overall status
Each of the 2,231 lake-type units reported by New York lands in exactly one overall-status bucket. On a register this large, the bar is an inventory partition, the cause chart and national gauge below answer different questions.
Most-listed impairment causes in New York
Waterbodies carrying each listed cause, most first
- pH
pH
211 waterbodies
- Phosphorus
Phosphorus
169 waterbodies
- Mercury
Mercury
95 waterbodies
- Dissolved Oxygen 80
Dissolved Oxygen
80 waterbodies
- Polychlorinated Biphenyls (PCBs) 56
Polychlorinated Biphenyls (PCBs)
56 waterbodies
What this shows pH is the most-listed impairment cause in New York, on 211 of the lake-type waterbodies reported there.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
New York: 88% of ruled verdicts are not-supporting, against a national share of 53%, 1.7× the national rate.
Reporting practice
A definitive verdict is still missing for most of New York's inventory
Each reporting authority decides how much of the water it files to EPA it actually assesses in a cycle. That decision sets the denominator behind every count on this page.
New York holds the 5th-largest reported lake-type inventory in the country, 2,231 assessment units, carrying a definitive verdict on 28.8% of it. The counts above describe the 642 units carrying a verdict, not all 2,231 reported. New York has also retired 9 lake-type assessment units, superseded filings that are kept on the site but not counted here.
The states reporting at the nearest rates are Minnesota (25.5%) and California (36.9%).
Assessing more of an inventory is a reporting choice, set by cycle length, monitoring budget and how finely a state splits its waters into units. It is not a measure of water quality, and it is why a raw count from one state does not sit beside a raw count from another. How assessment coverage varies.
New York against every comparable state
Share of reported lake-type waterbodies carrying a definitive verdict
28.8% 41st of 47 higher than 6 of 47 states
the 47 comparable states, by definitive-verdict share
Each bar is a band; taller bars hold more states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA ATTAINS · Reporting cycles 1987–2026
Each bar counts states whose definitive-verdict share falls in that 10-point band. The 47 states shown are those reporting at least 25 lake-type units; a share off a smaller inventory is precision the data does not have.
By size
Largest assessed lakes in New York
By assessed acreage as reported in ATTAINS. Acreage is the assessed unit's size, which can differ from a lake's full surface area.
| # | Waterbody | Assessed acres |
|---|---|---|
| 1 | Lake Champlain, Main Lake, Middle Not Supporting | 54,972 |
| 2 | Oneida Lake Not Supporting | 51,269 |
| 3 | Seneca Lake, Main Lake, Middle Fully Supporting | 40,290 |
| 4 | Cayuga Lake, Main Lake, Mid-South Fully Supporting | 33,083 |
| 5 | Lake George Not Supporting | 28,523 |
| 6 | Great Sacandaga Lake Not Supporting | 24,722 |
| 7 | Lake Champlain, Main Lake, North Not Supporting | 18,335 |
| 8 | Keuka Lake Fully Supporting | 11,678 |
| 9 | Canandaigua Lake Not Supporting | 10,528 |
| 10 | Lake Champlain, Main Lake, South Not Supporting | 10,455 |
| 11 | Chaumont Bay Not Supporting | 9,640 |
| 12 | Henderson Bay Not Supporting | 8,817 |
By cause count
Most-listed waterbodies in New York
Waterbodies carrying the most listed impairment causes among the lake-type units reported by New York.
| # | Waterbody | Listed causes |
|---|---|---|
| 1 | Onondaga Lake, southern end Not Supporting | 9 |
| 2 | Mattituck (Marratooka) Pond Not Supporting | 6 |
| 3 | Lake Eaton Not Supporting | 5 |
| 3 | Lake Ontario Shoreline, Western Not Supporting | 5 |
| 3 | Onondaga Lake, northern end Not Supporting | 5 |
| 3 | Rochester Embayment - East Not Supporting | 5 |
| 3 | Rochester Embayment - West Not Supporting | 5 |
| 3 | Rollins Pond Not Supporting | 5 |
| 9 | Bear Lake Not Supporting | 4 |
| 9 | Lake Ontario Shoreline, Central Not Supporting | 4 |
8 of the 10 rows in this table tie on the ranked value: 6 at 5 (rank 3), 2 at 4 (rank 9). Tied rows share a rank and are listed in no meaningful order; where a tie reaches the top the medal is shared, because nothing separates those rows.
Gauge network
Lakes with a daily level record in New York
Lakes with a linked USGS gauge and a daily water-level record. Readings are daily-batch snapshots, not real-time.
- Lake George Not Supporting USGS gauge 04278000 Level record →
- Great Sacandaga Lake Not Supporting USGS gauge 01323500 Level record →
- Ashokan Reservoir Not Supporting USGS gauge 01363400 Level record →
- Owasco Lake Not Supporting USGS gauge 04235396 Level record →
- Stillwater Reservoir Not Supporting USGS gauge 04256500 Level record →
- Pepacton Reservoir Not Supporting USGS gauge 01414750 Level record →
- Cannonsville Reservoir Not Supporting USGS gauge 01423910 Level record →
- Saratoga Lake Not Supporting USGS gauge 01330884 Level record →
- Hinckley Reservoir Not Supporting USGS gauge 01343900 Level record →
- Delta Reservoir Not Supporting USGS gauge 01335900 Level record →
- Rondout Reservoir Not Supporting USGS gauge 01366400 Level record →
- Neversink Reservoir Not Supporting USGS gauge 01435900 Level record →
States near New York's heavier not-supporting load
Two EPA ATTAINS peer sets outside New York. The reporting-practice chart above stays on definitive-verdict share; the neighborhoods below emphasize cross-state nearest neighbors when the not-supporting count is in the upper third.
States with a similar reported inventory
Nearest states by lake-type units on the register (2,231 here).
- New Hampshire · 2,786 units · 555 off
- Indiana · 1,588 units · 643 off
- Florida · 1,475 units · 756 off
- Oregon · 1,431 units · 800 off
Similar not-supporting load
Nearest states by units assessed not supporting a use (563 here). Inventory peers above are omitted.
- New Jersey · 583 not supporting · 20 off
- Wisconsin · 493 not supporting · 70 off
- Massachusetts · 678 not supporting · 115 off
- Illinois · 434 not supporting · 129 off
Peers are nearest-neighbor matches on EPA ATTAINS register size and not-supporting counts among states with at least 25 reported units. Impairment peers skip states already listed in the inventory column so the two link sets stay distinct.
Using this state picture
- Comparisons across states hold on shares, not counts: 28.8% of the inventory reported from New York carries a definitive verdict, 41st of 47 comparable states. National rankings
- Fish-consumption verdicts here are assessment decisions. Species-level meal advice comes from the state fish-advisory program. Consumption guide
- Browse every named New York waterbody with a populated record. Browse waterbodies
PlainLakes renders state assessment decisions and federal gauge observations without modification.
Figures on this page are computed from the assessment decisions New York reported to EPA's ATTAINS system and from USGS National Water Information System daily values, no number is typed in by an editor. State counts aggregate every lake-type assessment unit reported by New York, including unnamed units that never receive their own page. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-08-17. Primary sources: EPA ATTAINS and USGS National Water Information System.