Senate bill on carbon dioxide wells threatens rural water supplies

The U.S. Senate is considering legislation that will weaken groundwater protections, pertaining to wells engineered for long-term storage of carbon dioxide.

The language in question is buried in the last section of a larger water resources package, titled “Non-potable Aquifer Exemption for Class VI Wells” from the Water Resources Development Act of 2026 . This section would direct EPA “to provide for exemptions that allow the use of non-potable aquifers for Class VI wells.”

There are two exemptions in the bill. One applies if “the aquifer, or portion of the aquifer, does not currently serve as a source of drinking water” and “cannot now and will not in the future serve as a source of drinking water.” The other applies if “the total dissolved solids content of the ground water from the aquifer, or portion of the aquifer,” is between 3 and 10 grams per liter, and “the aquifer, or portion of the aquifer, is not reasonably expected to supply a public water system.”

That may sound complex, but here’s the reality: These two exemptions would discriminate against small rural communities and especially harm rural ranchers and farmers, because they could exempt irrigation water and water used for livestock watering operations. The problem is that just because people aren’t drinking or aren’t expected to drink the water, it follows that its content is irrelevant.

In addition, the exemptions would allow these carbon dioxide wells to be situated beneath or near aquifers that, while not being used currently for drinking water by people, could be in the future given the availability of reverse osmosis and other emerging water treatment technologies.

If a Class VI well were to leak carbon dioxide into an aquifer used for irrigation and livestock, it would acidify the water and mobilize heavy metals and potentially other toxic materials rendering it unusable in agriculture or for any drinking water purposes now or in the future.

Well documented well failures at injection wells in Illinois and Texas have shown that carbon capture injection wells need more stringent protections, not less.

This legislation would have had a direct impact on a proposed project in Montana, exempting certain aquifers from review when EPA considers Class VI well permits. The Snowy River Carbon Sequestration Project was a proposed ExxonMobil (via Denbury Carbon Solutions) facility in southeastern Montana’s Carter County designed to inject 150 million tons of carbon dioxide underground over 20 years. The carbon dioxide was to be primarily sourced from Wyoming gas plants and sequestered via up to 15 wells.

Landowners, including farmers and ranchers, were opposed because they saw no meaningful economic benefit but rather threats to range land and livelihoods, including degradation of surface and groundwater resources. The EPA found the Bureau of Land Management environmental assessment of potential impacts on groundwater aquifers inadequate. These included several shallow alluvial plain aquifers and a deeper sandstone aquifer. The shallower aquifers were primarily used for watering livestock, although they did qualify as underground sources of drinking water.

Facing heavy local and environmental scrutiny over agricultural disruption, groundwater threats, and pipeline safety, the bureau scaled back its review. Instead of approving the entire project footprint, the agency authorized only a single stratigraphic test well on state land to collect geologic and hydrologic data. Recently, Exxon removed the permit application , in large part due to the massive local opposition. However, projects like this one have a greater chance of moving forward if the law is changed to permit these carbon dioxide wells to be sited near aquifers used for rural wells and watering livestock.

This bill, exempting aquifers not currently used for drinking water (by people), imperils the livelihoods of small rural communities dependent on ranching and farming. It should be stopped.

Ted Schettler is science director at the Science and Environmental Health Network . Liz Barbour is a southeastern Montana rancher, rural advocate, and community organizer who led local opposition to the proposed Snowy River Carbon Sequestration Project.