Delaware reservoir · state assessment record
Tub Mill Pond
Assessment decisions reported by Delaware to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2012 reporting cycle.
- 10
- Assessed acres
- Lake / Reservoir / Pond
- Water type
This waterbody in one line
Tub Mill Pond, a reservoir in Delaware, is assessed as not supporting one or more designated uses, with one listed impairment cause in the state's most recent Integrated Report cycle (2012). By assessed acreage it sits among the smaller assessed lakes nationally (38,628 lakes with a filed area); its impairment list is among the longest nationally (one listed cause vs 23,610 assessed lakes). Aquatic life is assessed as not supporting.
- Not Supporting
- overall status
- P20
- Assessed size nationally
- P20
- Shorter cause list
- Not Supporting
- aquatic life
Assessment verdicts are the state agency's decisions as reported to EPA ATTAINS; PlainLakes renders them without modification.
A composite of this record's EPA ATTAINS designated-use verdicts, filed impairment count, and assessment currency, weighted and benchmarked against the national corpus of assessed active waterbodies. This is a water-quality standing, not a human-recreation or property-value judgment, and dimensions with no filed verdict drop out rather than count against the score.
Reading Tub Mill Pond's filed record
Paragraphs are selected by this unit's percentiles and use matrix: different lakes lead with different dimensions. Figures are ATTAINS / portal register arithmetic, not advice.
The signature stat: in-state cause rank
Inside Delaware, this unit sits toward the short-list end: cause-list rank 40 of 46 indexed units.
Every filed use falls short
On the uses this filer ruled on, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Tub Mill Pond: Category 4A reading
Category 4A means a TMDL (or equivalent) is already approved for the impairment on Tub Mill Pond. The remaining work is implementation and tracking, read the cleanup-standing and cause rows for what the state already committed to address.
Small within Delaware
State size rank 45 of 46 puts Tub Mill Pond toward the small end of Delaware's indexed lake-type units with an area.
Small assessed unit
10.3 acres puts Tub Mill Pond in the lower tercile by assessed area. Small units are often beaches, ponds, or segments, read the water-type and co-filed notes before comparing them to a multi-thousand-acre reservoir.
According to the U.S. Environmental Protection Agency's ATTAINS program, Delaware carries 47 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Tub Mill Pond without modification. See our methodology for reporting-unit limits and gauge linking rules.
The record
Designated-use assessments
Fully Supporting and Not Supporting are the state's definitive verdicts; other entries mean the use was not conclusively assessed in this cycle.
| Designated use | Group | Verdict |
|---|---|---|
| Fish, Aquatic Life, and Wildlife | Aquatic-life or related | Not Supporting |
The record
Listed impairment causes
Causes the state listed as impairing designated uses of this reservoir, with the cycle each was first listed and the Clean Water Act action recorded against it.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Nutrients | Fish, Aquatic Life, and Wildlife | 1996 | TMDL approved |
Reading the record
Tub Mill Pond: Category 4A reading
4A Category 4A: impaired, TMDL completed
Delaware filed this assessment unit as Category 4A: impaired, with a pollutant-budget TMDL already completed under 303(d). The listing remains an impairment finding; the plan is on file rather than still awaiting write-up.
Scale and rank
Tub Mill Pond is one of 47 lake-type waterbodies reported to EPA from Delaware, and one of 46 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 10 assessed acres it ranks 31,064th by assessed size among the 38,628 lakes the dataset carries an area for, counting a state’s repeated filings of one water once, behind 31,063 lakes with a larger one.
Not yet on record
The state has not yet filed a definitive fish-consumption verdict and a definitive recreation verdict for this record; those fields populate when it reports them in a future Integrated Report cycle.
In context
Where Tub Mill Pond sits nationally
Assessed size among U.S. lakes
Distribution of assessed acreage across ATTAINS lakes filed with an area, counting a state’s repeated filings of one water once
10 Top 80% larger than 20% of 38,628 lakes
lakes the dataset carries an area for, counting a state’s repeated filings of one water once, bucketed by value
Source EPA ATTAINS · Reporting cycles 1987–2026
Listed causes vs waterbodies carrying a verdict
How many impairment causes U.S. waterbodies with a reported verdict carry
1 Longer than most more listed causes than 49% of 23,610 waterbodies carrying a verdict
named waterbodies carrying a verdict, bucketed by value
Source EPA ATTAINS · Reporting cycles 1987–2026
In both charts each bar is a band and taller bars hold more waterbodies; the dashed line and filled bar mark Tub Mill Pond. Hover or tap any bar for its full count and share.
In context
Delaware context
ATTAINS carries 47 lake-type waterbodies in Delaware, 40 assessed as not supporting at least one use and 6 fully supporting. Among the 46 indexed units there, Tub Mill Pond ranks 40th by listed-cause count (one listed cause) and 45th by assessed size among the 46 with an area filed; it sits in the not-supporting set (40 statewide) . Its listed causes include Nutrients, which also appears among Delaware's most-filed impairment causes (led by Enterococcus).
| Other large assessed lakes in Delaware | Assessed acres |
|---|---|
| Lums Pond Fully Supporting | 198 |
| Red Mill Pond Fully Supporting | 192 |
| Hoopes Reservoir Not Assessed | 188 |
| Noxontown Pond Fully Supporting | 178 |
| Silver Lake Not Supporting | 168 |
| Millsboro Pond Not Supporting | 134 |
Peers near Tub Mill Pond's size or cause load
Similar assessed acres
Nearest filed extents (10 acres here).
- Indian Camp Lake · 10 acres · WI
- Tyler · 10 acres · MN
- Pops Hobby Lake-02050101002450 · 10 acres · PA
- Jenson Lake · 10 acres · WI
Similar cause load
Nearest listed-cause counts (1 here). Peers already in the acreage column are omitted.
- Aaron · 1 causes · MN
- Aaron River Reservoir · 1 causes · MA
- Abbotts Creek (including Lexington-Thomasville Water Supply Reservoir at normal reservoir elevation, Tom-A-Lex Lake) · 1 causes · NC
- Abeniki Lake · 1 causes · NH
What to do with this record
- Assessment verdicts are cycle-based, not real-time. For fish-consumption decisions, your state advisory program is the binding source. Consumption status guide
- Impairment listings follow the Clean Water Act 303(d) process; a listing is a regulatory finding, not a closure notice. 303(d) explained
PlainLakes renders state assessment decisions and federal gauge observations without modification. It does not issue advisories.
Assessment decisions on this page are rendered directly from state Integrated Report records in EPA's ATTAINS system; gauge figures are daily-value observations from the USGS National Water Information System, no number is typed in by an editor. Overall status, use verdicts, and causes are the state's reported decisions for assessment unit DE210-L01. Counts and percentiles are computed across all lake-type records PlainLakes ingests from ATTAINS. 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.