Pit, pond or lagoon on the subject property

The site visit or an aerial photograph shows a pit, pond or lagoon on the subject property, or where one was filled. The standard makes them a thing to look for and gives them no class. Whether there is a recognized environmental condition (REC) depends on four things: what the depression holds or held, what fed it and for how long, whether anything has left it, and whether it was closed or filled, and how.

What the answer turns on

What it holds or held. A REC needs hazardous substances or petroleum products, and a release, a likely release or a material threat of one (E1527-21, 3.2.73). The standard's pits, ponds or lagoons are natural or man-made depressions in the ground that likely contain liquid or sludge with those substances in it, a likelihood judged from evidence that includes discolored water, distressed vegetation and an obvious wastewater discharge (E1527-21, 3.2.64). The practice includes no sampling (E1527-21, 7.4). Its wastewater, unlike plain stormwater, has been used in industry or manufacturing, has carried sewage, or is directly tied to manufacturing, processing or raw materials storage at an industrial plant (E1527-21, 3.2.97). Establish whether the depression takes stormwater, process water, sewage or waste, and from where.
What fed it, and for how long. The environmental professional considers what releases past uses could have led to (E1527-21, 8.3.1). The standard's appendixes are nonmandatory. For a likely release, the one on the REC definition points to operations involving hazardous substances or petroleum products, how long they ran and in what period (E1527-21, X4.1). Establish who used it, for what, over which years.
Whether anything has left it. The legal background appendix reports the federal agency's reading that a release into the environment takes in pipe discharges into open ponds or lagoons, and any other discharge not held wholly inside a building or structure (E1527-21, X1.1.1.1, footnote 21). It also describes a bar on recovering response costs for federally permitted releases, among them discharges in compliance with Clean Water Act discharge and pretreatment permits, and a savings clause that leaves obligations under other federal or state law unchanged (E1527-21, X1.1.4.3, footnote 87). The body of the standard does not say how a permit weighs on a REC. Establish whether it overflows or discharges, and what the soil, water and plants around it show; odors, stained soil and stressed vegetation are site visit features (E1527-21, 9.4.13, 9.4.23, 9.4.24). A release that is found is weighed against the de minimis definition (E1527-21, 3.2.20): see staining on pavement or soil.
Whether it was closed or filled, and how. Ground that appears graded or filled with fill of unknown origin, and depressions, are site visit features where they suggest solid waste disposal (E1527-21, 9.4.25): see fill of unknown origin. A past release addressed to the applicable regulatory authority's satisfaction may be a historical REC or a controlled REC, by whether unrestricted use criteria were met without controls; the professional reviews the closure documentation, such as a no further action letter (E1527-21, 3.2.17, 3.2.17.1, 3.2.39).

For the federal hazardous waste rules, a surface impoundment is a natural depression, excavation or diked area made mainly of earthen materials, lined or not, designed to hold liquid waste or waste with free liquids, other than an injection well; the definition's examples are quoted below (40 CFR 260.10). A facility that treats, stores or disposes of hazardous waste may consist of one or more surface impoundments (40 CFR 260.10), and the federal list of such facilities is a standard source (RCRA TSD; E1527-21, 8.2.2, Table 2). These rules classify nothing under the standard.

The records that bear on it

Site visit. Pits, ponds and lagoons, and liquid discharged from or to the subject property, stormwater included, are described in the report, or reported as not found (E1527-21, 9.4, 9.4.22, 9.4.26). Bodies of water that limit observation are noted and documented (E1527-21, 9.2.6).
Historical sources. Aerial photographs and historical topographic maps are reviewed where the professional judges them applicable, likely to be useful and reasonably ascertainable (E1527-21, 8.3.8). Look in them for when it appeared, what drained to it, and when it was filled.
Interviews and documents. Questions shall try to cover such features, current and past (E1527-21, 10.2). The owner, key site manager and user are asked for solid waste, hazardous waste disposal, wastewater and discharge permits, reports on hydrogeologic conditions and reports of any cleanup (E1527-21, 10.8.1). New Mexico's agency says a discharge to a lined lagoon or a holding tank needs a permit in most cases (New Mexico), and Kentucky's lists surface impoundments, lagoons, pits or ditches holding pollutants among the activities that call for a groundwater protection plan (Kentucky).

What the federal rule says

Among what the inquiry must seek to identify, the inquiry rule (40 CFR part 312) lists

Waste management and disposal activities that could have caused releases or threatened releases of hazardous substances;

40 CFR 312.20(e)(1)(iii), edition revised as of July 1, 2025

For a party seeking the liability protections that item stops at hazardous substances; the standard includes petroleum products (E1527-21, 1.1.2).

The hazardous waste definitions, on the surface impoundment:

Examples of surface impoundments are holding, storage, settling, and aeration pits, ponds, and lagoons.

40 CFR 260.10, edition revised as of July 1, 2025

How it is written up

The depression is a finding when the professional judges it may indicate hazardous substances or petroleum products present or likely present at the subject property (E1527-21, 12.5).

Where the professional concludes such substances were placed in the depression or left it, or likely were, and are present or likely present at the subject property, the opinion gives the grounds: what fed it, over which years, what has left it, the evidence. Unless judged a de minimis condition or a historical REC, the REC is listed in the Conclusions, and the professional should give an opinion on additional investigation, if any (E1527-21, 3.2.20, 3.2.39, 12.7, 12.8).

Where the professional concludes otherwise, the opinion on a finding gives its reasoning on the same four facts (E1527-21, 12.6). Whether a discharge met its permit is regulatory compliance, outside the standard's scope unless the user adds it (E1527-21, 13.1.2, 13.1.5.14).

Historical sources for the years the depression was in use, or observation of its banks on the site visit, may be what cannot be had. Required information that good faith efforts could not obtain is a data gap, significant if it affects the ability to identify a REC: named in the Findings with the sources consulted, discussed in the Opinions and listed in the Conclusions (E1527-21, 3.2.19, 3.2.78, 12.5.1, 12.6.2, 12.7).

This page is general reference for environmental professionals. It does not classify any property. ASTM E1527-21 is the standard and is not reproduced here; the judgment of the environmental professional on the facts governs.