June 27, 2026.
The debate surrounding Enbridge’s Line 5 pipeline continues to intensify across Michigan and Wisconsin as multiple court cases, permit disputes, tribal rights issues, and environmental concerns move forward in 2026. While Enbridge argues that Line 5 is a critical piece of energy infrastructure serving the Midwest and eastern Canada, opponents contend that the aging pipeline and proposed expansion projects pose unacceptable risks to the Great Lakes, tribal lands, and freshwater resources.
Recent developments include ongoing litigation over the Line 5 tunnel beneath the Straits of Mackinac, renewed efforts by Michigan regulators to permit the discharge of tunnel construction wastewater into Lake Michigan, legal challenges involving the Bad River Band in Wisconsin, and growing public opposition to water withdrawals supporting pipeline construction activities.
Michigan’s Line 5 Court Battles Continue
One of the most significant developments this year occurred in April when the U.S. Supreme Court unanimously ruled that Michigan’s lawsuit seeking to shut down Line 5 beneath the Straits of Mackinac will remain in state court rather than being moved to federal court. The lawsuit, originally filed in 2019 by Michigan Attorney General Dana Nessel, argues that Enbridge does not have a legal right to occupy the bottom-lands beneath the Straits and that continued operation of the pipeline poses environmental risks to the Great Lakes.
The decision was procedural rather than a ruling on the merits of the case, but it represents a significant victory for Michigan officials who have long sought to challenge the legality of the pipeline’s continued operation beneath the Straits of Mackinac. The state maintains that a rupture in the pipeline could have catastrophic consequences for both Lake Michigan and Lake Huron, which meet at the Straits.
At the same time, separate litigation continues regarding Governor Gretchen Whitmer’s 2020 effort to revoke the easement that allows Line 5 to operate beneath the Straits. Federal courts have thus far prevented Michigan from enforcing that shutdown order, finding that pipeline safety regulation falls primarily under federal jurisdiction.
The Michigan Supreme Court also heard arguments in March 2026 concerning approvals granted for Enbridge’s proposed tunnel project beneath the Straits. Tribal nations and environmental organizations have challenged decisions by the Michigan Public Service Commission that authorized construction of the tunnel. Opponents argue that stateregulators failed to adequately consider environmental impacts, treaty rights, and alternatives to the project.
The Wastewater Discharge Controversy.
A major new flashpoint involves Enbridge’s request to discharge treated construction wastewater into Lake Michigan as part of the proposed Line 5 tunnel project.
In May 2026, Michigan’s Department of Environment, Great Lakes, and Energy (EGLE) announced plans to reissue a key wastewater discharge permit that had previously expired. The proposed permit would allow Enbridge to discharge up to five million gallons per day of treated tunnel construction water, groundwater seepage, slurry treatment wastewater, cooling water, and other construction-related fluids into Lake Michigan during tunnel construction.
Environmental organizations, tribal governments, and Great Lakes advocates have raised serious concerns about the proposal. Critics argue that the wastewater could contain drilling additives, sediment, oil residue, and other contaminants associated with tunnel boring operations. Opponents contend that Enbridge has not adequately demonstrated that the discharges would be harmless to the Straits of Mackinac ecosystem or the fisheries that support tribal treaty rights and local economies.
Public hearings were held to allow regulators gather testimony on the proposal. Most Northern Michigan Tribal Nations have urged citizens to submit comments opposing the permit, arguing that the discharge of millions of gallons of construction wastewater into one of the world’s largest freshwater systems creates unnecessary environmental risks.
The wastewater issue has become a central concern because the tunnel project itself remains under federal review. While Michigan regulators have approved portions of the project, Enbridge still requires additional state and federal permits before tunnel construction can begin beneath the Straits.
Bad River Reroute Construction Faces Continued Legal Challenges.
While Michigan battles continue, Enbridge has begun construction on a separate but related project in northern Wisconsin. The company is building a 41-mile reroute around the Bad River Reservation after a federal judge ruled that Enbridge was trespassing on tribal land.
In 2023, U.S. District Judge William Conley ordered Enbridge to remove or reroute the pipeline segment crossing the reservation and awarded more than $5 million in damages to the Bad River Band. The judge initially required the company to complete the reroute by June 2026. However, in March 2026, he paused that shutdown order pending appeal, citing potential economic and energy supply consequences if the pipeline were abruptly closed.
Construction on the estimated $450 million reroute officially began on February 24, 2026. Enbridge reports that more than 500 workers are now engaged in the project.The reroute crosses approximately 186 waterways and affects more than 100 acres of wetlands, making environmental oversight a major issue throughout construction.
Despite construction activity, legal challenges continue. Environmental organizations have sought judicial review of permits issued for the reroute, and in May 2026 a Wisconsin judge ordered a partial halt to certain construction activities involving several waterway crossings pending further review.
Ashland Residents Protest Water Use for Line 5 Construction.
The latest controversy emerged in Ashland, Wisconsin, where residents have begun protesting the use of municipal water supplies to support Line 5 construction activities.
According to local residents, trucks operated by Michels Construction, an Enbridge contractor, have been observed filling water tanks at the City of Ashland’s water station. Protesters allege that the water is being used in horizontal directional drilling operations associated with the Line 5 reroute project.
Horizontal directional drilling allows pipelines to pass beneath rivers, wetlands, and other sensitive resources without open trench excavation. According to project documents, Enbridge plans to install approximately 30,000 feet of pipeline beneath 23 waterways using this technique. The process requires large volumes of water mixed with bentonite clay and other additives to lubricate drilling equipment and stabilize boreholes.
Residents argue that the public was never adequately informed about agreements involving city water supplies and question how much Lake Superior water may ultimately be used during construction. They also express concerns about the possibility of inadvertent drilling fluid releases, commonly known as “frac-outs,” which can occur when drilling slurry escapes into surrounding soils or waterways.
Protesters have pointed to obligations under the Great Lakes–St. Lawrence River Basin Water Resources Compact, often called the Great Lakes Compact. They argue that water withdrawn from the Great Lakes basin should be returned in a clean condition and that the public deserves greater transparency regarding water withdrawals and disposal practices associated with pipeline construction.
The issue also intersects with tribal treaty rights. Some residents contend that water use and potential contamination risks could affect natural resources protected under treaties with Anishinaabe nations, including the Bad River Band.
Enbridge maintains that the reroute project is among the most extensively reviewed infrastructure projects in Wisconsin history and that all construction activities comply with state and federal environmental requirements. The company has stated that impacts will be temporary and that the project will not violate tribal water quality standards or treaty-protected resources. Meanwhile, the Bad River Band and environmental groups continue to challenge permits associated with the project in court.
What Comes Next?
The future of Line 5 remains uncertain. Multiple court cases continue in both Michigan and Wisconsin. The Michigan Supreme Court is weighing challenges to tunnel approvals, the state court shutdown lawsuit remains active, federal regulators continue reviewing tunnel permits, and public opposition to wastewater discharges and construction impacts shows no signs of slowing.
For tribal nations, environmental advocates, and many Great Lakes residents, the central question remains whether the risks associated with Line 5 can ever be justified in one of the world’s most valuable freshwater ecosystems. For Enbridge and its supporters, the focus remains on maintaining a vital energy corridor while replacing aging infrastructure with what the company describes as safer alternatives.
As legal proceedings continue and regulators review permits, the Line 5 debate remains one of the most consequential environmental and infrastructure conflicts in the Great Lakes region.
