Proposed Rule Changes Would Affect Groundwater Monitoring At Legacy Oilfield Sites

The Louisiana Department of Conservation and Energy (C&E) recently released proposed rule changes regarding groundwater management, consolidating existing water well rules into Title 43, Part VI of the La. Administrative Code and proposing new rules that may affect current practices for evaluating groundwater at legacy oilfield sites. 

Separately Evaluating Groundwater Zones

To investigate potential impacts to groundwater at an oilfield site, an interested party typically installs monitoring wells to sample and test water at various depths below the land surface. Under the proposed revisions, monitoring wells would be classified within a new, broader category of “environmental wells,” defined as water wells “usually installed in an area of known or suspected contamination used to obtain hydrologic data, water quality data, information on water resources of an area, or to recover or treat contaminated groundwater.” 

Environmental wells and other water wells contain screens set at certain depths to allow the influx of groundwater. The proposed rules contain a new provision stating that no water well or environmental well may have a screen that extends across more than one distinct aquifer layer, and that connecting two or more distinct water-bearing zones is “strictly prohibited.” As a result, parties would be required to separately evaluate each distinct groundwater zone by installing a separate screen or well for each zone.

Plugging Environmental Wells

The pending revisions also add rules for plugging environmental wells. Existing regulations require that all abandoned wells be plugged within 90 days of their abandonment. Under the proposed revisions, environmental wells would be considered abandoned on the earliest date on which “they no longer serve a purpose, they are damaged beyond repair or the project they are associated with is terminated,” whereupon the owner of the well would be responsible for plugging the environmental well within 30 days. This would appear to clarify that each monitoring well installed in conjunction with the investigation of a legacy oilfield site must be promptly plugged by the party who installed it upon the conclusion of the investigation and any associated agency or court proceedings.

Other Proposed Changes

In addition to the changes discussed above, C&E is proposing changes on other topics, such as management of groundwater resources by lowering the threshold for “large volume” water wells from 1,500 to 300 gallons per minute, thus expanding the water-producing wells that would be subject to metering, monitoring, and production limits. The proposed changes would also allow C&E to create “Areas of Investigation” in order to collect data on certain aquifers that could potentially be later designated as “Areas of Groundwater Concern” under La. R.S. 30:3097.6 of existing law, which focuses on aquifer supply and quality. C&E is soliciting comments on these and other proposed groundwater management rule changes through October 15, 2026, and you can download the full draft of the proposed changes here.