Some of these decisions are not final. 184 of these 554 records carry a verdict Nebraska decided in its 2026 Integrated Report, which is open for public comment, so they can change before the cycle is submitted to EPA. They are counted in every figure on this page.
Some of these decisions are EPA's. 1 of these 554 records carry at least one designated-use verdict or impairment listing EPA filed rather than Nebraska; on those, the determination is EPA's rather than Nebraska's. They are counted in every figure on this page, and each record page names which.
State water-quality picture · #18 by reported lake-type waterbodies
Nebraska lakes and reservoirs
Every figure on this page is computed from the assessment decisions Nebraska reported to the U.S. Environmental Protection Agency under Clean Water Act sections 303(d) and 305(b) (reporting cycles 2016–2026), plus daily water-level observations from the U.S. Geological Survey.
- 554
- Reported waterbodies
- 219
- Not supporting a use
- Not reported
- Fish use assessments
- 0
- Gauged lakes
Nebraska in one line
554 lake-type waterbodies in Nebraska are reported to EPA ATTAINS across reporting cycles 2016–2026: 219 assessed as not supporting at least one designated use, 138 fully supporting, and 197 without a definitive overall verdict. The most-listed impairment cause is Mercury in Fish Tissue, on 131 waterbodies. This ranks the cause names filed in Nebraska, not distinct pollutants: mercury appears under 2 of them, together listed on 132 waterbodies.
- 554
- reported waterbodies
- 219
- not supporting a use
- 138
- fully supporting
- 62%
- of definitive verdicts impaired
An unassessed waterbody is neither confirmed clean nor confirmed impaired; states assess on multi-year cycles. 5 of those 138 fully supporting verdicts rest on designated uses this site does not report (irrigation, navigation and industrial water supply), with Nebraska recording no verdict on fish consumption, recreation, aquatic life and drinking water. They are counted above because the state filed them, and excluded from the impaired share below because that figure compares states.
Nebraska's mid-pack EPA ATTAINS lake-type picture
554 reported units and a mid-third ruled-impairment footing (62% not supporting) - neither inventory extreme nor load extreme on this extract.
Data updated 2026-08-17
According to the U.S. Environmental Protection Agency's ATTAINS program, Nebraska reported 554 lake-type waterbodies in Nebraska in the August 2026 extract. See our methodology for filer attribution and multi-year reporting cycles.
Overall-status mix on Nebraska's mid-size inventory
Every reported lake-type unit in Nebraska falls into exactly one overall-status bucket. This bar is the inventory partition; the cause chart and national gauge below answer different questions.
Most-listed impairment causes in Nebraska
Waterbodies carrying each listed cause, most first
- Mercury in Fish Tissue
Mercury in Fish Tissue
131 waterbodies
- Phosphorus, Total
Phosphorus, Total
97 waterbodies
- Chlorophyll-a
Chlorophyll-a
94 waterbodies
- Nitrogen, Total
Nitrogen, Total
89 waterbodies
- pH
pH
53 waterbodies
What this shows Mercury in Fish Tissue is the most-listed impairment cause in Nebraska, on 131 of the lake-type waterbodies reported there. This ranks the cause names filed in Nebraska, not distinct pollutants: mercury appears under 2 of them, together listed on 132 waterbodies.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
Nebraska: 62% of ruled verdicts are not-supporting, against a national share of 53%, 1.2× the national rate.
Reporting practice
How much of the Nebraska inventory carries a definitive verdict
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.
Nebraska holds the 18th-largest reported lake-type inventory in the country, 554 assessment units, carrying a definitive verdict on 63.5% of it. The counts above describe the 352 units carrying a verdict, not all 554 reported. Nebraska has also retired 563 lake-type assessment units, superseded filings that are kept on the site but not counted here.
The states reporting at the nearest rates are Illinois (63.5%) and Massachusetts (60.3%).
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.
Nebraska against every comparable state
Share of reported lake-type waterbodies carrying a definitive verdict
63.5% 26th of 47 higher than 20 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 Nebraska
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 | Lewis and Clark Lake Not Supporting | 25,174 |
| 2 | Lake C. W. McConaughy Fully Supporting | 24,868 |
| 3 | Harlan County Reservoir Not Supporting | 12,821 |
| 4 | Calamus Reservoir Not Supporting | 5,028 |
| 5 | Swanson Reservoir Not Supporting | 4,660 |
| 6 | Sutherland Reservoir Fully Supporting | 2,954 |
| 7 | Merritt Reservoir Not Supporting | 2,543 |
| 8 | Sherman Reservoir Not Supporting | 2,432 |
| 9 | Johnson Lake Not Supporting | 2,206 |
| 10 | Lake Minatare (North Platte NWR) Not Supporting | 1,957 |
| 11 | Branched Oak Lake Not Supporting | 1,755 |
| 12 | Harry Strunk Lake (Medicine Creek Reservoir) Not Supporting | 1,726 |
By cause count
Most-listed waterbodies in Nebraska
Waterbodies carrying the most listed impairment causes among the lake-type units reported by Nebraska.
| # | Waterbody | Listed causes |
|---|---|---|
| 1 | Kirkman's Cove Lake Not Supporting | 7 |
| 2 | Burchard Lake (WMA) Not Supporting | 6 |
| 2 | Calamus Reservoir Not Supporting | 6 |
| 2 | Lake Hastings Not Supporting | 6 |
| 2 | Merritt Reservoir Not Supporting | 6 |
| 2 | Stagecoach Lake Not Supporting | 6 |
| 7 | Alexandria Lake No. 3 Not Supporting | 5 |
| 7 | Big Indian Lake (11A) Not Supporting | 5 |
| 7 | Bluestem Lake Not Supporting | 5 |
| 7 | Bowling Lake Not Supporting | 5 |
9 of the 10 rows in this table tie on the ranked value: 5 at 6 (rank 2), 4 at 5 (rank 7). 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.
States with similar inventory scale or impairment load
Two EPA ATTAINS peer sets outside Nebraska. The reporting-practice chart above stays on definitive-verdict share; these neighborhoods are cross-state nearest neighbors on register size and not-supporting counts.
States with a similar reported inventory
Nearest states by lake-type units on the register (554 here).
- Pennsylvania · 516 units · 38 off
- California · 607 units · 53 off
- New Jersey · 611 units · 57 off
- South Carolina · 611 units · 57 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: 63.5% of the inventory reported from Nebraska carries a definitive verdict, 26th 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 Nebraska 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 Nebraska 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 Nebraska, 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.