Some of these decisions are EPA's. 48 of these 144 records carry a Clean Water Act cleanup plan EPA established rather than Arkansas. They are counted in every figure on this page, and each record page names which.
State water-quality picture · #35 by reported lake-type waterbodies
Arkansas lakes and reservoirs
Every figure on this page is computed from the assessment decisions Arkansas reported to the U.S. Environmental Protection Agency under Clean Water Act sections 303(d) and 305(b) (reporting cycles 1992–2024), plus daily water-level observations from the U.S. Geological Survey.
- 144
- Reported waterbodies
- 62
- Not supporting a use
- 42
- Fish use not supporting
- 0
- Gauged lakes
Arkansas in one line
144 lake-type waterbodies in Arkansas are reported to EPA ATTAINS across reporting cycles 1992–2024: 62 assessed as not supporting at least one designated use, 55 fully supporting, and 27 without a definitive overall verdict. The most-listed impairment cause is Mercury in Fish Tissue, on 45 waterbodies.
- 144
- reported waterbodies
- 62
- not supporting a use
- 55
- fully supporting
- 53%
- of definitive verdicts impaired
An unassessed waterbody is neither confirmed clean nor confirmed impaired; states assess on multi-year cycles.
Arkansas's smaller reported lake-type inventory
At 144 units, Arkansas is in the lowest third of state lake-type registers. The charts below describe that compact filing set, not a national-scale inventory.
Data updated 2026-08-17
According to the U.S. Environmental Protection Agency's ATTAINS program, Arkansas reported 144 lake-type waterbodies in Arkansas in the August 2026 extract. See our methodology for filer attribution and multi-year reporting cycles.
Overall-status split on Arkansas's compact register
Every reported lake-type unit in this smaller Arkansas filing set falls into exactly one overall-status bucket. The bar partitions 144 units; cause and gauge panels below stay separate.
Most-listed impairment causes in Arkansas
Waterbodies carrying each listed cause, most first
- Mercury in Fish Tissue
Mercury in Fish Tissue
45 waterbodies
- pH 8
pH
8 waterbodies
- Nutrients 6
Nutrients
6 waterbodies
- Turbidity - Storm Flows 3
Turbidity - Storm Flows
3 waterbodies
- Dissolved Oxygen 2
Dissolved Oxygen
2 waterbodies
What this shows Mercury in Fish Tissue is the most-listed impairment cause in Arkansas, on 45 of the lake-type waterbodies reported there.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
Arkansas: 53% of ruled verdicts are not-supporting, against a national share of 53%, in line with the national rate.
Reporting practice
A definitive verdict covers nearly all of Arkansas'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.
Arkansas holds the 35th-largest reported lake-type inventory in the country, 144 assessment units, carrying a definitive verdict on 81.3% of it. The counts above describe the 117 units carrying a verdict, not all 144 reported. Arkansas has also retired 28 lake-type assessment units, superseded filings that are kept on the site but not counted here.
The states reporting at the nearest rates are Maryland (79.4%) and Virginia (84%).
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.
Arkansas against every comparable state
Share of reported lake-type waterbodies carrying a definitive verdict
81.3% 18th of 47 higher than 29 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 Arkansas
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 | Dardanelle Lake Fully Supporting | 34,041 |
| 2 | Millwood Lake Assessment unit AR_11140109_4020 Fully Supporting | 29,500 |
| 3 | Ouachita Lake Fully Supporting | 24,695 |
| 4 | Bull Shoals Assessment unit AR_11010003_4011 Not Supporting | 22,046 |
| 5 | Greers Ferry Lake Assessment unit AR_11010014_4021 Fully Supporting | 18,151 |
| 6 | Felsenthal Lake Not Supporting | 14,000 |
| 7 | Norfork Lake Not Supporting | 13,833 |
| 8 | Beaver Lake Fully Supporting | 13,546 |
| 9 | Greers Ferry Lake Assessment unit AR_11010014_4020 Fully Supporting | 12,883 |
| 10 | Bull Shoals Assessment unit AR_11010003_4010 Not Supporting | 11,498 |
| 11 | Millwood Lake Assessment unit AR_11140109_4021 Fully Supporting | 10,344 |
| 12 | De Gray Lake Fully Supporting | 9,299 |
By cause count
Most-listed waterbodies in Arkansas
Waterbodies carrying the most listed impairment causes among the lake-type units reported by Arkansas.
| # | Waterbody | Listed causes |
|---|---|---|
| 1 | Cox Creek Lake Not Supporting | 3 |
| 2 | Horseshoe Lake Not Supporting | 2 |
| 2 | Lake Frierson Not Supporting | 2 |
| 2 | Nimrod Lake Not Supporting | 2 |
| 2 | Pickthorne Lake Not Supporting | 2 |
| 2 | Winona Lake Assessment unit AR_08040203_4100 Not Supporting | 2 |
| 2 | Winona Lake Assessment unit AR_08040203_4101 Not Supporting | 2 |
| 8 | Bear Creek Lake Not Supporting | 1 |
| 8 | Beaver Lake Assessment unit AR_11010001_4042 Not Supporting | 1 |
| 8 | Beaver Lake Assessment unit AR_11010001_4041 Not Supporting | 1 |
9 of the 10 rows in this table tie on the ranked value: 6 at 2 (rank 2), 3 at 1 (rank 8). 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 near Arkansas's lighter not-supporting load
Two EPA ATTAINS peer sets outside Arkansas. The reporting-practice chart above stays on definitive-verdict share; these neighborhoods highlight register-size and not-supporting peers while Arkansas's ruled impairment share sits in the lowest third.
Similar reported inventory
Nearest states by lake-type units on the register (144 here).
Comparable not-supporting counts
Nearest states by units assessed not supporting a use (62 here). Inventory peers above are omitted.
- Louisiana · 64 not supporting · 2 off
- North Dakota · 52 not supporting · 10 off
- Idaho · 51 not supporting · 11 off
- New Mexico · 46 not supporting · 16 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: 81.3% of the inventory reported from Arkansas carries a definitive verdict, 18th 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 Arkansas 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 Arkansas 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 Arkansas, 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.