ML26063A011
| ML26063A011 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 02/26/2026 |
| From: | Central Coast Regional Water Quality Control Board |
| To: | Office of Nuclear Material Safety and Safeguards |
| References | |
| 34024WQ31 | |
| Download: ML26063A011 (0) | |
Text
CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD CENTRAL COAST REGION Order:
Clean Water Act Section 401 Water Quality Certification for Federal License ORDER NUMBER:
34024WQ31 PROJECT:
Operating License Renewal for Diablo Canyon Power Plant Units 1 and 2 FACILITY:
Diablo Canyon Power Plant PERMITTEE:
Pacific Gas & Electric Company 1250 Kendall Road San Luis Obispo, CA 93424 EFFECTIVE DATE:
February 26, 2026 ACTION:
- 1.
Order for Standard Certification
- 2.
Order for Technically Conditioned Certification (Order)
- 3.
Order for Denial of Certification I. PROJECT DESCRIPTION AND BACKGROUND A. Pacific Gas & Electric Company (Permittee) is the owner and operator of the Diablo Canyon Power Plant (Facility), a nuclear power plant. The Facility is a nuclear steam electrical power generation facility consisting of two pressurized reactors (Units 1 and 2), each serving as an independent generating unit.
Additional Facility infrastructure includes a turbine building, a seawater reverse osmosis system, storage tanks, a cooling water intake structure, and discharge structure. The Facility has a total generating capacity of 2,269 megawatts and provides energy services to California.
B. Consistent with the direction of the California State Legislature as described in Senate Bill 846 (2022) and California Water Code section 13193.5, the Permittee seeks to continue Facility operations, which requires renewal of the operating licenses for the Facility issued by the United States Nuclear Regulatory Commission (NRC). Since continued operations of the Facility will result in discharges into navigable waters of the United States as part of the plants cooling water system and other operations, the California Regional Water Quality Control Board, Central Coast Region (Central Coast Water Board) must issue a
PACIFIC GAS AND ELECTRIC CO.
ORDER 34024WQ31 DIABLO CANYON POWER PLANT 2
Clean Water Act section 401 Water Quality Certification before the NRC can issue renewed licenses. Clean Water Act section 401 requires applicants for federal licenses who will discharge to navigable waters of the United States to obtain certification from the State that the discharges will comply with water quality standards. The Permittee previously obtained a Certificate of Conformance with water quality standards from the Central Coast Water Board for the Facility in 1971.
C. The Facilitys point source discharges to navigable waters of the United States are subject to permitting under the National Pollutant Discharge Elimination System (NPDES) permitting program. The primary NPDES permit applicable to the Facility addresses wastewater discharges from the once-through cooling system and other waste streams. This NPDES permit was previously issued by the Central Coast Water Board in 1990 (Waste Discharge Requirements for Pacific Gas and Electric Company Diablo Canyon Nuclear Power Plant Units 1 and 2, Order 90-09, NPDES Permit CA0003751).1 Since that time, various water quality standards, plans, and policies have been enacted and/or updated. The new NPDES permit (Waste Discharge Requirements for the Pacific Gas and Electric Companys Diablo Canyon Power Plant, Order R3-2026-0001, NPDES Permit CA0003751) for the Facilitys wastewater discharges incorporates all applicable new and/or updated water quality standards, plans, and policies, including requirements set forth in the Water Quality Control Policy on the Use of Coastal and Estuarine Waters for Power Plant Cooling (Once-Through Cooling Policy). The Facilitys industrial stormwater discharges are also subject to Order WQ 2014-0057-DWQ, as amended by Order WQ 2015-0122-DWQ and Order WQ 2018-0028-DWQ, General Permit for Storm Water Discharges Associated with Industrial Activities, NPDES Permit CAS000001. This Order requires compliance with the NPDES permits issued for the Facility to certify compliance with water quality standards.
II. REGULATORY AUTHORITY A. The federal Clean Water Act (33 U.S.C. sections 1251-1388) was enacted to restore and maintain the chemical, physical, and biological integrity of the Nations waters. (33 U.S.C. section 1251(a).) The Clean Water Act relies significantly on state participation and support in light of the primary responsibilities and rights of States to prevent, reduce, and eliminate pollution and plan the development and use of water resources. (33 U.S.C. section 1251(b).) Section 101 of the Clean Water Act (33 U.S.C. section 1251(g))
requires federal agencies to co-operate with State and local agencies to develop comprehensive solutions to prevent, reduce and eliminate pollution in concert with programs for managing water resources. (33 U.S.C. section 1251(g).)
1 The permit has been administratively extended since 1994. See California Code of Regulations, title 23, section 2235.4; title 40 Code of Federal Regulations section 122.6 subd. (d).
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ORDER 34024WQ31 DIABLO CANYON POWER PLANT 3
Section 401 of the Clean Water Act (33 U.S.C. section 1341) requires any applicant for a federal license or permit that may result in a discharge into navigable waters to provide the licensing or permitting federal agency with certification that the project will comply with specified provisions of the Clean Water Act, including water quality standards and implementation plans promulgated pursuant to section 303 of the Clean Water Act. (33 U.S.C. section 1313.) Clean Water Act section 401 directs the agency responsible for certification to prescribe effluent limitations and other conditions necessary to ensure compliance with the Clean Water Act and with any other appropriate requirement of State law. (33 U.S.C. section 1341(d).) Section 401 further provides that certification conditions shall become conditions of any federal license or permit for the project. (Ibid.)
B. The Central Coast Water Board is authorized to issue Clean Water Act section 401 Water Quality Certification for this Facility pursuant to California Water Code section 13263 and California Code of Regulations, title 23 (23 CCR), section 3855.
C. This Order is granted pursuant to Clean Water Act section 401 and its implementing regulations (title 40 Code of Federal Regulations (40 CFR) part 121) and California Water Code sections 13263 and 13377 and implementing regulations 23 CCR division 3, chapter 28.
III. FINDINGS:
The Central Coast Water Board hereby finds that:
A. WATER QUALITY FINDINGS:
- 1. Waste Discharge Requirements for the Pacific Gas and Electric Companys Diablo Canyon Power Plant, Order R3-2026-0001, NPDES Permit CA0003751, last issued in 1990, has been updated to include all current water quality objectives identified in the Water Quality Control Plan for the Central Coastal Basin (Basin Plan), the Water Quality Control Plan for Ocean Waters of California (Ocean Plan), the Clean Water Act and its implementing regulations, and all applicable State Water Resources Control Board plans and policies, including but not limited to the Once-Through Cooling Policy.
- 2. The Once-Through Cooling Policy establishes uniform technology-based standards to implement the requirements of Clean Water Act section 316(b) and reduce the harmful effects associated with cooling water intake structures on marine and estuarine life. The terms and conditions of the Once-Through Cooling Policy apply to the Facility, and relevant requirements are incorporated into Waste Discharge Requirements for the Pacific Gas and Electric Companys Diablo Canyon Power Plant, Order R3-2026-0001,
PACIFIC GAS AND ELECTRIC CO.
ORDER 34024WQ31 DIABLO CANYON POWER PLANT 4
NPDES Permit CA0003751 at section 6.3.6.1.
- 3. Waste Discharge Requirements for the Pacific Gas and Electric Companys Diablo Canyon Power Plant, Order R3-2026-0001, NPDES Permit CA0003751 was adopted on February 26, 2026, prior to the time this Order was considered and adopted by the Central Coast Water Board.
- 4. Compliance with the terms and conditions in set forth in this Order, as well as compliance with Waste Discharge Requirements for the Pacific Gas and Electric Companys Diablo Canyon Power Plant, Order R3-2026-0001, NPDES Permit CA0003751 and Order WQ 2014-0057-DWQ, as amended by Order WQ 2015-0122-DWQ and Order WQ 2018-0028-DWQ, General Permit for Storm Water Discharges Associated with Industrial Activities, NPDES Permit CAS000001, ensures that the Project will comply with specified provisions of the Clean Water Act, including Clean Water Act sections 301, 302, 303, 306, and 307.
- 5. All public noticing requirements were satisfied prior to the adoption of this Order. Specifically, the Central Coast Waer Board complied with California Water Code section 13167.5, 40 CFR section 124.10, 40 CFR part 25, and 23 CCR section 3858.
- 6. The Central Coast Water Board acted within a reasonable period of time in adopting this Order, as required pursuant to 40 CFR section 121.6 (see also 40 CFR 121.8) and within 180 days of receiving a completed application for certification, pursuant to California Public Resource Code section 25233.2 subdivision (c).
B. CALIFORNIA ENVIRONMENTAL QUALITY ACT FINDINGS:
- 1. The Central Coast Water Board has determined that the Project is exempt from review under the California Environmental Quality Act (CEQA) pursuant to California Code of Regulations, title 14, section 15061. Specifically, the issuance of this Order and the activities described herein meet the exemption criteria under California Code of Regulations, title 14, section 15301 subd. (b),
and California Code of Regulations, title 15, section 25548.2 subd. (b).
Additionally, the Central Coast Water Board concludes that no exceptions to the CEQA exemption apply to the activities approved by this Order.
PACIFIC GAS AND ELECTRIC CO.
ORDER 34024WQ31 DIABLO CANYON POWER PLANT 5
IV. CONDITIONS A. STANDARD CONDITIONS:
- 1. This Order is subject to modification or revocation upon administrative or judicial review, including review and amendment per California Water Code section 13330 and 23 CCR section 3867.
- 2. This Order is not intended to apply to any discharge from any activity involving a hydroelectric facility requiring a Federal Energy Regulatory Commission (FERC) license or an amendment to a FERC license unless the pertinent application was filed per 23 CCR subsection 3855(b) and the application specifically identified that a FERC license or amendment to a FERC license was being sought. In this case, no such application has been sought.
- 3. The validity of this Order is conditioned upon total payment of the fee required under 23 CCR section 3833, unless otherwise stated in writing by the certifying agency.
B. GENERAL COMPLIANCE CONDITIONS:
- 1. This Order is subject to the Permittees acquisition of all local, regional, state, and federal permits and approvals as required by law. Failure to meet any conditions contained herein or any conditions contained in any other permit or approval issued by the State of California or any subdivision thereof may result in the revocation of this Order and civil or criminal liability.
- 2. In the event of a violation or threatened violation of this Order, the violation or threatened violation shall be subject to any remedies, penalties, process, or sanctions as provided for under state law. For purposes of Clean Water Act section 401(d), the applicability of any state law authorizing remedies, penalties, process, or sanctions for the violation or threatened violation constitutes a limitation necessary to ensure compliance with the water quality standards and other pertinent requirements incorporated into this Order.
- 3. In response to a suspected violation of any condition of this Order, the California Regional Water Quality Control Board, Central Coast Region (Central Coast Water Board) may require the holder of any permit or license subject to this Order to furnish, under penalty of perjury, any technical or monitoring reports the Central Coast Water Board deems appropriate, provided that the burden, including costs, of the reports shall have a reasonable relationship to the need for the reports and the benefits obtained from the reports.
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ORDER 34024WQ31 DIABLO CANYON POWER PLANT 6
- 4. In response to any violation of the conditions of this Order, the Central Coast Water Board may add to or modify the conditions of this Order as appropriate to ensure compliance.
- 5. The Central Coast Water Board reserves the right to suspend, cancel, or modify and reissue this Order, after providing notice to the Permittee, if the Central Coast Water Board determines that the Project fails to comply with any of the terms or conditions of this Order.
- 6. A copy of this Order, the application, and supporting documentation must be available at the Facility for review by site personnel and agencies.
- 7. The Permittee shall grant the Central Coast Water Board, or an authorized representative, upon presentation of credentials and other documents as may be required by law, permission to enter the Facility at reasonable times, to ensure compliance with the terms and conditions of this Order and/or to determine the impacts the Project may have on the quality of waters of the state.
- 8. The Permittee must, at all times, fully comply with the application, engineering plans, specifications, and technical reports submitted to support this Order; all subsequent submittals required as part of this Order; and the conditions of this Order. The conditions within this Order supersede conflicting provisions within Permittee submittals.
- 9. The Permittee shall notify the Central Coast Water Board within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of any unauthorized discharge to waters of the United States or waters of the state, including measures that were implemented to stop and contain the discharge; measures implemented to clean up the discharge; the volume and type of materials discharged and recovered; and additional best management practices or other measures that will be implemented to prevent future discharges.
- 10. This Order is not transferable to any person except after notice to the Executive Officer of the Central Coast Water Board. The Permittee shall submit this notice in writing at least 30 days in advance of any proposed transfer. The notice must include a written agreement between the existing and new responsible party containing a specific date for the transfer of this Order's responsibility and coverage between the current responsible party and the new responsible party. This agreement shall include an acknowledgement that the existing responsible party is liable for compliance and violations up to the transfer date and that the new responsible party is liable from the transfer date on.
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ORDER 34024WQ31 DIABLO CANYON POWER PLANT 7
- 11. This Order expires when the Nuclear Regulatory Commission licenses for Units 1 and 2 of the Facility, expected to be issued in 2026, expire.
- 12. The total application fee for the Project is $4,212. The remaining project fee payable to the Central Coast Water Board is $0. Annual fees apply while this Order remains in effect.
C. TECHNICAL CONDITIONS:
- 1. Project activities and discharges must not cause a violation of any water quality standard, including impairment of designated beneficial uses, as adopted in the Basin Plan, the Ocean Plan, or any other applicable water quality control plans or policies.
- 2. The Permittee shall comply with the requirements of Waste Discharge Requirements for the Pacific Gas and Electric Companys Diablo Canyon Power Plant, Order R3-2026-0001, NPDES Permit CA0003751 and any accompanying requirements, including future modifications and future reissuances.
- 3. The Permittee shall comply with the Once-Through Cooling Policy and all related requirements, including any future modifications to the Policy.
- 4. The Permittee shall comply with State Water Resources Control Board Order WQ 2014-0057-DWQ, as amended by Order WQ 2015-0122-DWQ and Order WQ 2018-0028-DWQ, General Permit for Storm Water Discharges Associated with Industrial Activities, NPDES Permit CAS000001, including future modifications and future reissuances.
- 5. The Permittee shall employ the reasonable and prudent measures identified in the National Marine Fisheries Service Biological Opinion, dated April 22, 2025, to minimize the impact of the incidental take on sea turtles and black abalone.
- 6. This Order authorizes normal ongoing operation of the Diablo Canyon Power Plant. It does not authorize new discharges into waters of the United States or waters of the state, including new discharges of dredge or fill material that have not previously been authorized.
CENTRAL COAST WATER BOARD CONTACT PERSON:
April Woods (805) 549-3332 April.Woods@waterboards.ca.gov
PACIFIC GAS AND ELECTRIC CO.
ORDER 34024WQ31 DIABLO CANYON POWER PLANT 8
Please refer to the above order number when corresponding with the Central Coast Water Board concerning this Project.
WATER QUALITY CERTIFICATION:
The Central Coast Water Board hereby issues an order certifying that, as long as all the conditions listed in this Order are met, Project activities and discharges shall comply with the applicable provisions of sections 301, 302, 303, 306, and 307 of the Clean Water Act. Project activities and discharges are also regulated pursuant to Waste Discharge Requirements for the Pacific Gas and Electric Companys Diablo Canyon Power Plant, Order R3-2026-0001, NPDES Permit CA0003751 and Order WQ 2014-0057-DWQ, as amended by Order WQ 2015-0122-DWQ and Order WQ 2018-0028-DWQ, General Permit for Storm Water Discharges Associated with Industrial Activities, NPDES Permit CAS000001.
Except insofar as may be modified by any preceding conditions, all Order actions are contingent on (a) the activities and discharges being limited and all proposed mitigation being completed in strict compliance with the Permittees Project description and Order conditions and (b) compliance with all applicable requirements of the Central Coast Water Boards Basin Plan, the Ocean Plan, and any other applicable water quality control plans or policies.
This Order is effective on February 26, 2026.
I, Ryan E. Lodge, Executive Officer, do hereby certify that this Order with all attachments is a full, true, and correct copy of an order adopted by the California Regional Water Quality Control Board, Central Coast Region on the date indicated above.
Ryan E. Lodge Executive Officer Central Coast Water Board Attachment A: Project Information Ryan E.
Lodge Digitally signed by Ryan E. Lodge Date: 2026.02.27 07:06:51 -08'00'
PACIFIC GAS AND ELECTRIC CO.
ORDER 34024WQ31 DIABLO CANYON POWER PLANT ATTACHMENT A 1
ATTACHMENT A - PROJECT INFORMATION Application Date Received: December 13, 2024 Completed: September 4, 2025 Permittee Pacific Gas & Electric Company 1250 Kendall Road San Luis Obispo, CA 93401 Permittee Representatives Thomas P. Jones Pacific Gas and Electric Company 1250 Kendall Road San Luis Obispo, CA 93401 Tom.Jones@pge.com (805) 459-4530 Kris Vardas Pacific Gas and Electric Company 1250 Kendall Road San Luis Obispo, CA 93401 Kris.Vardas@pge.com (805) 975-5229 Project Operating License Renewal for Diablo Canyon Power Plant Units 1 and 2 Order Number 34024WQ31 Type of Project Utilities - Alternative energy (Other)
Project Location Avila Beach 35°1244N, 120°5114W County San Luis Obispo Receiving Water(s)
Pacific Ocean Diablo Creek HU 310 Estero Bay Water Body Type Ocean Streambed Designated Beneficial Uses Pacific Ocean Industrial Service Supply (IND)
Water Contact Recreation (REC-1)
Non-Contact Recreation (REC-2)
Wildlife Habitat (WILD)
Migration of Aquatic Organisms (MIGR)
Spawning, Reproduction, and/or Early Development (SPWN)
Rare, Threatened or Endangered Species (RARE)
Navigation (NAV)
Commercial and Sport Fishing (COMM)
Shellfish Harvesting (SHELL)
Marine Habitat (MAR)
PACIFIC GAS AND ELECTRIC CO.
ORDER 34024WQ31 DIABLO CANYON POWER PLANT ATTACHMENT A 2
Designated Beneficial Uses Diablo Canyon Creek Municipal and Domestic Supply (MUN)
Agricultural Supply (AGR)
Industrial Service Supply (IND)
Ground Water Recharge (GWR)
Water Contact Recreation (REC1)
Non-Contact Water Recreation (REC2)
Wildlife Habitat (WILD)
Cold Fresh Water Habitat (COLD)
Spawning, Reproduction, and/or Early Development (SPAWN)
Rare, Threatened, or Endangered Species (RARE)
Estuarine Habitat (EST)
Fresh Water Replenishment (FRESH)
Commercial and Sport Fishing (COMM)
Project Description (purpose/goal)
The purpose of the Project is to continue operation and maintenance of Units 1 and 2 of the Diablo Canyon Power Plant. The Project includes the following operations involving seawater intake and discharges:
- 1. Intake of seawater through an intake structure.
- 2. Circulation of the seawater in a once-through cooling circulating water system to remove heat from condensers.
- 3. Discharge of up to 2,760 million gallons per day of once-through cooling water and the following other commingled waste streams.
- a. auxiliary seawater cooling system
- b. liquid radioactive waste treatment system
- c. service cooling water system
- d. turbine building sump
- e. makeup water system waste effluent
- f. condensate demineralizer regenerant
- g. condensate pumps discharge header overboard
- h. steam generator blowdown
- i. wastewater holding and treatment system
- j. sanitary wastewater treatment system
- k. seawater reverse osmosis system blowdown
- l. intake structure building sumps overboard
- 4. Discharge of the following additional waste streams.
- a. screen wash pumps overboard
- b. intake screen wash water
- c. seawater reverse osmosis system supply tank overflow
- d. biolab seawater supply pump valve drain
- e. seawater reverse osmosis system blowdown drain
- f. seawater reverse osmosis system supply lines drain
- g. main circulating water pumps backflow
- h. screen wash system collection sump overflow
- 5. Treatment of seawater by reverse osmosis to provide freshwater for various uses.
PACIFIC GAS AND ELECTRIC CO.
ORDER 34024WQ31 DIABLO CANYON POWER PLANT ATTACHMENT A 3
United States Nuclear Regulatory Commission Nuclear Regulatory License Renewal Application for Facility Operating Licenses DPR-80 and DPR-82 for Diablo Canyon Power Plant Units 1 and 2 California Environmental Quality Act Information Categorical Exemption Lead Agency: California Regional Water Quality Control Board, Central Coast Region Total Fee
$4,212