The Central Coast Regional Water Quality Control Board approved a wastewater discharge permit and a new water quality certification necessary to keep the lights on at Diablo Canyon Power Plant.
The unanimous decision made on Feb. 26 drew criticism from the Santa Lucia Chapter of the Sierra Club, San Luis Obispo Mothers for Peace, and Committee to Bridge the Gap.
“I was not surprised by the water board’s approval, but I am disappointed,” Committee to Bridge the Gap Executive Director Haakon Williams said. “The state Legislature’s official policy is that Diablo Canyon is not authorized to operate beyond 2030; a state agency should not be issuing certifications with expiration dates extending far beyond the timeframe authorized by state law.”
The water board reviewed the National Pollutant Discharge Elimination System permit and the Clean Water Act Section 401 water quality certification.
The national discharge system permit regulates how Diablo Canyon discharges desalination brine, treated wastewater, and warmed water used to cool the plant’s spent fuel pools and safety components. The permit allows Diablo Canyon owner Pacific Gas & Electric Company (PG&E) to discharge 2.7 million gallons of wastewater a day.
PG&E now awaits the Nuclear Regulatory Commission’s decision to extend plant operations through August 2045. But before the commission can issue the license, section 401 of the federal Clean Water Act requires the water board to certify that waste discharges from Diablo Canyon comply with all provisions of the act, including state water quality standards.
The three public interest groups called for the water board to only approve the Clean Water Act certification under the condition that PG&E doesn’t run the plant after the 2030 expiration date set by Senate Bill 846.
The groups also claimed precedent.
In 2017, New York’s Indian Point Nuclear Power Plant owner Entergy Corporation amended its Nuclear Regulatory Commission (NRC) license renewal application to specify an earlier closing date. The decision was part of an agreement with New York state that stemmed from the New York Department of Environmental Conservation’s proposed denial of Entergy’s section 401 certification.
“The Central Coast water board must follow the precedent established at Indian Point and require, as a condition of its approval of the section 401 certification, that PG&E amend its NRC license renewal application to set a 2030 expiration date,” the West Coast groups said in a joint statement. “This would ensure that Diablo Canyon does not continue to degrade California waters beyond the timeframe authorized by the state.”
‘A state agency should not be issuing certifications with expiration dates extending far beyond the timeframe authorized by state law.’
—Haakon Williams, Committee to Bridge the Gap executive director
But the water board approved the certification as proposed by staff—it will expire simultaneously with the renewed federal operating license.
“So, it’s not a defined date, but a fluid date that will be set once NRC issues its license,” Williams said. “There are rumors that the state Legislature will, later this year, consider a bill to extend Diablo Canyon another 15 years. State agencies like the water board should be regulating based on existing law, not Legislature rumors. Unfortunately, that is not what happened.”
Water board staff didn’t respond to New Times’ questions about the water quality certification and referred to the meeting recording instead. Staff’s responses to comments from the public noted that while reducing the water quality certification’s lifespan is an option, it’s not preferred.
“By linking the proposed 401 certification expiration with the NRC license expiration, the proposed 401 certification avoids conflicts with potential future legislation, should future legislation extend the date when DCPP operations are to cease beyond 2030,” staff response read. “It is also worth noting that the Central Coast water board is not required to include an expiration date in the 401.”
Sophie Froelich, an attorney with the State Water Resources Control Board, said at the meeting that the NRC generally issues a license for 20 years. According to her, there’s concern that shortening the validity of the water quality certification to less that 20 years “could be infringing on the power” of the federal body.
She added that the supposed ties to Indian Point power plant aren’t relevant to the discussion, and that the New York plant was embroiled in complicated litigation.
“It was all decided that that plant, as a result of that litigation, would shut down at a particular point, and that the license would end,” Froelich said. “I see absolutely no parallels between that agreement and what we’re doing here today. There is no pending litigation, there is nothing to settle.” ∆
This article appears in March 5-12, 2026.