Monitoring wells of unknown origin

The site visit finds monitoring wells on the subject property, and no record or person says who put them in or why. Federal rules use such wells in more than one way, so a well alone does not say what it was for or what it found. Whether a recognized environmental condition (REC) goes with the wells depends on four things: what the wells were for, what the sampling found, where the release they follow began, and whether the matter was closed and how.

What the answer turns on

A REC is hazardous substances or petroleum products present at the subject property because of a release, likely present owing to a release or a likely one, or present where conditions make a future release a material threat (E1527-21, 3.2.73). The standard lists monitoring wells among the wells the site visit looks for and the report describes (E1527-21, 9.4, 9.4.27). It does not say what a monitoring well means.

What the wells were for. The federal tank rule, 40 CFR part 280, allows vapor monitoring and groundwater monitoring among its methods of release detection for petroleum tanks installed by April 11, 2016, each with monitoring wells in or near the tank excavation (40 CFR 280.41(a), 280.43); for groundwater monitoring the wells "intercept the excavation zone or are as close to it as is technically feasible" (40 CFR 280.43(f)(5)). Wells beside a tank system may therefore be leak detection equipment and not the trace of a release. The rule also counts its closure assessment as met where one of those two methods is operating at closure and shows no release (40 CFR 280.72(a)). The same rule has owners and operators investigate soil and groundwater after some confirmed releases (40 CFR 280.60, 280.65), and the federal rule for municipal solid waste landfills describes a groundwater monitoring system of wells (40 CFR 258.51).
What the sampling found. The standard's appendixes are nonmandatory. Appendix X4 gives data from analyzing samples of environmental media taken at the subject property as one kind of direct evidence of a release (E1527-21, X4.1). The standard includes no sampling (E1527-21, 7.4), so the results come from reports and files.
Where the release began. Wells on the subject property may follow a release that began elsewhere. By Appendix X4, a REC cannot lie off the subject property, though an off-site release that has migrated to it can cause one (E1527-21, X4.1). The standard notes that activity and use limitations may be used to give access to monitoring wells (E1527-21, 5.3), so a recorded instrument may explain wells that another party installed.
Whether the matter was closed, and how. A release addressed to the regulatory authority's satisfaction raises the historical and controlled REC definitions: unrestricted use criteria met with no controls, or contamination left in place under required controls (E1527-21, 3.2.17, 3.2.39).

The records that bear on it

Documents and interviews. The owner, key site manager and user are asked whether they know of environmental site assessment reports, site investigation reports, reports on hydrogeologic conditions and cleanup reports (E1527-21, 10.8, 10.8.1). Past owners, operators and occupants likely to have material information are interviewed where identified (E1527-21, 10.5.4).
Government records and the file. Check the leaking tank list, state hazardous waste sites and voluntary cleanup sites for the subject property and its neighbors, and the registered tank list for a tank system the wells may serve. For a listed subject property or adjoining property the file should be reviewed, or the report explains why not (E1527-21, 8.2.3.1). Pennsylvania says the records its agency routinely makes available include monitoring well records.
Title records and controls. The user's search for recorded activity and use limitations, and the registries of state and federal controls, may show a control that goes with the wells (E1527-21, 6.2, 8.2.2).
Officials. A reasonable attempt is made to interview a state or local official; the choices include the agency with jurisdiction over environmental matters in the area (E1527-21, 11.5.1).
Site visit. The report's site plan shows the approximate location of the features the professional judges relevant (E1527-21, 12.3). Adjoining properties are observed from the subject property and public thoroughfares (E1527-21, 9.2.5), which may show wells continuing beyond the boundary.

What the federal rule says

The inquiry rule, 40 CFR part 312, does not mention monitoring wells. For the subject property it says the records review should include

Records of reported releases or threatened releases, including site investigation reports for the subject property;

40 CFR 312.26(b)(1)

Of the wells used for release detection at a tank system, the tank rule says:

Monitoring wells are clearly marked and secured to avoid unauthorized access and tampering.

40 CFR 280.43(e)(7)

Of a municipal solid waste landfill, 40 CFR part 258 says:

A ground-water monitoring system must be installed that consists of a sufficient number of wells, installed at appropriate locations and depths, to yield ground-water samples from the uppermost aquifer

40 CFR 258.51(a)

Neither of those two rules classifies anything under the standard.

How it is written up

Wells identified at the subject property are described in the report (E1527-21, 9.4). They become a finding when the environmental professional judges they may indicate presence or likely presence at the subject property, and the opinion reasons for or against calling the matter a REC (E1527-21, 12.5, 12.6).

Where the records or the data show a release at the subject property, or the professional concludes one is likely, the opinion gives the grounds. 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 (E1527-21, 3.2.20, 3.2.39, 12.7, 12.8).

Where the wells are explained, as leak detection or as monitoring with no release shown, the opinion says so and gives its reasoning (E1527-21, 12.6).

Where the origin stays unknown, the professional weighs the lines of evidence the assessment did produce, the report documents the sources checked, and the professional should give an opinion on additional investigation, if any (E1527-21, 7.3.1, 8.1.9, 12.8). The installer's report would come closest to settling it.

The interview with the key site manager, or with a regulatory official, may be what could not be held. 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.