The three-year WMP cycle and what changes between filings
A California wildfire mitigation plan is filed once per cycle and revised repeatedly inside it. Energy Safety publishes a per-utility calendar ending in a fork: a draft decision or a revision notice. Southern California Edison's 2026-2028 plan reached Revision 4 by June 26, 2026. Public Utilities Code section 8386(b) requires a plan every four years.
Southern California Edison's wildfire mitigation plan for 2026 through 2028 was due at the Office of Energy Infrastructure Safety on May 16, 2025. Thirteen months later the version on the docket is Revision 4, filed June 26, 2026, with an errata filing on top of it dated August 26, 2026.
In between, the plan's pole clearing targets were rewritten because the state ordered it, and its covered conductor and undergrounding targets were rewritten because the California Public Utilities Commission funded something different. A three-year plan is filed once. It changes many times inside those three years, and every change lands on somebody's scope of work.
The cycle runs on a published calendar, one utility at a time
Energy Safety publishes a schedule before each cycle and revises it as it goes. The revised 2026-2028 Base WMP schedule issued February 24, 2025 gives each utility its own dates. SCE's row reads:
Item | Date |
Pre-submission due | March 28, 2025 |
Energy Safety provides pre-submission check findings | April 11, 2025 |
Submission due | May 16, 2025 |
Substantive errata due | June 2, 2025 |
Opening comments due | June 27, 2025 |
Nonsubstantive errata due | June 30, 2025 |
Reply comments due | July 7, 2025 |
Energy Safety issues draft decision or revision notice | August 15, 2025 |
Two things in that table matter more than the rest. The first is that a plan is checked before it is evaluated: a pre-submission goes in seven weeks early and comes back with findings. The second is the last row, which is a fork rather than a date. Energy Safety either drafts a decision or issues a revision notice, and which one arrives determines whether the plan is close to final or about to be rewritten.
The dates are staggered across the industry. The same schedule set six more submission deadlines in the same cycle.
Electrical corporation | Submission due |
Pacific Gas and Electric Company | April 4, 2025 |
Bear Valley Electric Services | April 18, 2025 |
San Diego Gas & Electric Company | May 2, 2025 |
Liberty Utilities | June 27, 2025 |
PacifiCorp | July 11, 2025 |
Independent transmission owners | July 25, 2025 |
Seven submission dates, one docket.
Timing is mechanical. The Energy Safety Policy Division Process Guidelines state that anything submitted after 5:00 p.m. Pacific Time on a business day is deemed received the next business day, and an extension request has to arrive at least two business days before the original deadline.
A revision notice is where the plan actually changes
The authority sits in Public Utilities Code section 8386.3(a)(2), in one sentence:
Before approval, the office may require modifications of the plan.
Energy Safety exercises it through a revision notice. Its own description of the instrument is plain:
The Office of Energy Infrastructure Safety (Energy Safety) may direct an electrical corporation to modify its Wildfire Mitigation Plan (WMP) by issuing a Revision Notice. ... Critical issues are areas of significant concern that an electrical corporation must address prior to the completion of Energy Safety's evaluation.
SCE's arrived on August 15, 2025, the exact date the schedule had reserved for the fork. It listed 10 critical issues, each with a tracking code and a required remedy, and gave SCE until September 15, 2025 to file both a response and a redlined revised plan.
Six of the ten were vegetation management. One of them, RN-SCE-26-06, is the clearest example of why a bidder reads these. SCE's plan carried pole clearing targets in Table 9-2 with a footnote attached:
Attempts where no structures are found, or no clearance is required, are counted towards the target.
A second footnote added attempts where property access was not granted. Energy Safety's remedy was one sentence:
SCE must revise its 2026-2028 Base WMP to remove footnotes 4 and 5 of Table 9-2 and must stop equating attempts to inspect with completed inspections when establishing its targets.
That is a definition of a unit changing inside a cycle. Under the footnote, a crew that drives to a location, finds nothing to clear and leaves has produced a unit against the target. Without it, the utility owes the state a completed clearance.
The same notice required SCE to revise its VM-7 and VM-8 inspection targets to cover 100 percent of its High Fire-Threat District and High Fire Risk Area, because the stated targets and the described scope of the inspections did not match. What counts, and how much of the territory it has to cover, both moved between R0 and R1.
Rejection and denial are the other two exits
A revision notice assumes the plan is reviewable. Two harder outcomes exist.
A plan can be rejected before substantive review begins. On June 24, 2025, Energy Safety rejected SDG&E's May 2, 2025 submission and ordered a resubmission by July 11, 2025:
SDG&E's 2026-2028 Base WMP does not conform to the requirements outlined in Energy Safety Guidelines, and a conforming plan must be submitted before Energy Safety can continue its substantive evaluation.
A plan can also be denied outright at the end. Energy Safety denied Liberty Utilities (CalPeco Electric) LLC's 2026-2028 plan on April 1, 2026, after publishing a draft of that decision on February 18, 2026 and taking opening comments to March 9 and reply comments to March 19.
The decision assessed Liberty's R1, dated December 4, 2025, and found that the revision notice response and the substantive errata that followed it had not closed five of the ten critical issues. Liberty was ordered to improve its risk model and file a new plan between August and November 2026.
An approved plan is the first of the seven conditions behind a utility safety certification, which is why a denial is not a paperwork event. The work itself does not stop. The document that authorizes the spending does.
Errata are the utility's own corrections, and they close fast
Errata and revisions get confused because both produce a new version number. The Process Guidelines separate them:
An erratum is a correction of published text by the electrical corporation and does not include revisions required by Energy Safety as part of the Revision Notice process.
There are two kinds, on two clocks.
Substantive errata | Nonsubstantive errata | |
What it covers | Corrections to targets, calculations, initiatives that materially impact the evaluation | Minor corrections to typographical errors or clarity |
Window without a request | 10 business days after the submission deadline | 30 business days after the submission deadline |
After the window | Written request to the Deputy Director required | Not provided for |
Every errata filing carries a cover letter stating whether it is substantive or nonsubstantive, the page, section and table number of each correction, a description, a reason, and a redline of the affected pages. Classification is not the utility's call:
Classification of errata as substantive or nonsubstantive is solely within the discretion of Energy Safety.
The version numbers run continuously. The Process Guidelines state that "Base WMP versions begin at R0 with the first filing and continue through the three-year cycle." So R3 and R4 of a 2026-2028 plan are the same plan as R0, two years apart, with different numbers in the tables.
An approved plan can still be amended mid-cycle
The CPUC adopted decision D.25-09-030 on SCE's 2025 test year general rate case on September 18, 2025, five weeks after the revision notice and five months before the plan was approved. It authorized less undergrounding than SCE's plan had assumed. The route back into the plan is a petition to amend, governed by Chapter 4 of the WMP Guidelines.
The timing rule is genuinely ambiguous, and Energy Safety resolved it in a footnote. The Guidelines require a petition within 45 days of the relevant rate case decision, and also provide that a petition may only amend an approved plan. SCE's plan was not approved until February 23, 2026, months after the rate case decision. Energy Safety treated the April 9, 2026 petition as timely on that basis. Where the two rules collide, the office decides which one governs.
It approved all three amendments on June 12, 2026. The numbers moved like this:
Target | Approved plan, 2026-2028 | After amendment |
Covered conductor | 440 circuit miles | 775 circuit miles |
Covered conductor by year, 2026 / 2027 / 2028 | 240 / 125 / 75 | 200 / 280 / 295 |
Targeted undergrounding | 260 miles | 155 circuit miles |
Targeted undergrounding by year, 2026 / 2027 / 2028 | 75 / 100 / 85 | 55 / 50 / 50 |
Two further changes came with them. SCE's undergrounding unit of measurement changed from "de-energized overhead miles" to "underground circuit miles installed," which is a different count of the same construction. The Disability Disaster Access Resources program was removed from the plan entirely.
Energy Safety then set the follow-through.
Revise Table 6-3, Table 6-4 and Table 8-1 to carry the amended targets.
File the amended plan in the docket no later than June 26, 2026.
Revise data reporting to match, under Data Guidelines version 4.1.
R4 was filed on June 26, 2026. The chain from a rate case decision in September to a new number in a data submission the following summer took nine months and touched four documents. How a master services agreement handles volume that moves is where that chain reaches a contract, and AB 1054's own wiring of the two approvals is where the statutory sequence sits.
Four dates repeat every year inside the cycle
Approval does not end the filing calendar. Section 8386.3(b) and section 8386.3(c) set four recurring obligations, and each one is built from completion records.
Obligation | When | Source |
Utility self-evaluation report on the prior calendar year | On or before April 1 each year | Section 8386.3(b)(1) |
Independent evaluator report | On or before July 1 in each year a self-evaluation is filed | Section 8386.3(b)(2)(B)(i) |
Energy Safety performance review completed | Within 18 months of the self-evaluation report | Section 8386.3(b)(4) |
Advice letter before the annual vegetation management revenue requirement is exhausted | Not less than 30 days before the projected date | Section 8386.3(c)(1)(A) |
The last one is the one that reaches a crew soonest. A utility has to tell the Commission 30 days before it expects to have spent or committed its entire annual vegetation management budget. A notice like that is a signal about the back half of a program year. What the evaluator and the auditors look at when they arrive belongs to Energy Safety's audits.
The three-year cycle ends with this one
Public Utilities Code section 8386(b), as amended by SB 254 effective September 19, 2025, now reads:
Each electrical corporation shall submit a wildfire mitigation plan to the office for review at least once every four years. The office shall establish a schedule for the submission of subsequent comprehensive wildfire mitigation plans, which may allow for the staggering of evaluation and performance periods for each electrical corporation.
Four years is the statutory floor, and the schedule is Energy Safety's to set. Two letters since have done that work. A January 26, 2026 letter canceled the annual update that would otherwise have fallen inside the current cycle:
Energy Safety will not be accepting 2027 WMP Updates and will not be administering the WMP Maturity Survey in 2026.
An August 31, 2026 letter then fixed the submission dates:
Electrical corporation | Next submission | Period covered |
Pacific Gas & Electric Company | March 1, 2027 | 2028-2031 |
Bear Valley Electric Service | March 15, 2027 | 2028-2031 |
Southern California Edison Company | March 29, 2027 | 2028-2031 |
San Diego Gas & Electric Company | April 12, 2027 | 2028-2031 |
PacifiCorp | April 26, 2027 | 2028-2030 |
Liberty Utilities | May 10, 2027 | 2028-2030 |
PacifiCorp and Liberty file three-year plans rather than four-year ones, because the plan period follows the rate case period. Energy Safety's January 26, 2026 letter records that Liberty intends to stay on a three-year rate case cycle, and requires a small or multi-jurisdictional utility on a shorter cycle to coordinate with Energy Safety and file its plan one year before its rate case application.
Independent transmission owners do not file again until 2028. So the phrase "the WMP cycle" stops describing one thing on March 1, 2027: four utilities move to four-year plans, two stay on three, and the plan period is now pinned to each utility's own rate case rather than to a common calendar. The preliminary plan requirement that starts January 1, 2027 is the statutory hinge for that alignment.
What is not settled yet is the rest of the calendar. The August 31 letter says only that "future dates related to errata, public comments, and the issuances of draft Decisions/Modification Notices will be published later." The process those dates will govern is also being rewritten: Energy Safety published draft WMP Guidelines on September 1, 2026 and noticed a workshop on them for September 24, 2026 in the WMP Guidelines docket. Energy Safety decides both, and until it publishes them, a bid that assumes a particular review sequence is assuming.
Reading a scope of work against the right version
A solicitation that cites a wildfire mitigation plan is citing a document with a version number and a date, and both matter.
Ask which revision the volumes came from. SCE's 2026-2028 covered conductor number was 440 miles in the approved plan and 775 after June 12, 2026. A scope drafted against the approved plan and a scope drafted against R4 are different jobs.
Check whether the unit of measurement is the one in the current version. SCE's undergrounding unit changed from de-energized overhead miles to underground circuit miles installed in the same decision. Unit price mechanics turn on exactly that definition.
Read the vegetation management critical issues in the last revision notice. They are where the state tells a utility that a count it has been reporting does not count, and a no-access attempt that used to close a unit is the plainest example.
Watch the 2028-2031 filings in the spring of 2027. Those plans must report progress on every area for continued improvement named in the 2026-2028 decisions, so the remediation timelines and procedures Energy Safety criticized in this cycle are the ones being re-committed in the next.
Everything above sits in one public docket. The 2026-2028 Base WMPs docket holds every submission, revision notice, errata, comment and decision described here, filed under the utility's name and dated. A number in a request for proposal can be traced back to the version of the plan it came from in about ten minutes.
Further reading
How California utility Wildfire Mitigation Plans work under AB 1054: Why the plan carries commercial weight, and which agency approves what.
What a utility safety certification requires: An approved plan is the first of seven conditions behind the certificate.
What Energy Safety's audits actually examine: The annual reporting and audit obligations that run inside the cycle.
Frequently asked questions
How long is the WMP cycle?
Three years for the plans now in force, and four for most of the plans that follow. The 2023-2025 and 2026-2028 base plans were three-year plans, and Energy Safety's Policy Division Process Guidelines describe version numbering that runs 'through the three-year cycle.' Public Utilities Code section 8386(b), as amended by SB 254 effective September 19, 2025, requires a plan at least once every four years and gives Energy Safety the job of setting the schedule. Energy Safety's August 31, 2026 letter schedules 2028-2031 plans for PG&E, Bear Valley, SCE and SDG&E, and 2028-2030 plans for PacifiCorp and Liberty Utilities.
How many versions of one plan are there?
For SCE's 2026-2028 base plan, five and an errata filing. Versions begin at R0 with the first filing under Energy Safety's naming convention. SCE's submission was due May 16, 2025, Energy Safety issued a revision notice on August 15, 2025, the approved version cited in the June 12, 2026 petition decision was R3, Revision 4 was filed June 26, 2026, and errata followed on August 26, 2026.
What is a revision notice?
The instrument Energy Safety uses to direct changes to a plan before it decides. Its authority is Public Utilities Code section 8386.3(a), which allows the office to require modifications before approval. A notice lists critical issues with tracking codes and a required remedy for each, and sets a response deadline. SCE received one on August 15, 2025 with 10 critical issues and a September 15, 2025 response date.
Can a wildfire mitigation plan be denied?
Yes. Energy Safety denied the Liberty Utilities (CalPeco Electric) LLC 2026-2028 Base WMP on April 1, 2026, after five of the 10 critical issues in its revision notice went unresolved through R1 and substantive errata. The decision required Liberty to improve its risk model and submit a new plan between August and November 2026.
What happens to plan targets after a rate case decision?
They can be amended by petition. The CPUC adopted decision D.25-09-030 on SCE's 2025 test year on September 18, 2025. SCE filed a petition to amend on April 9, 2026, and Energy Safety approved it on June 12, 2026, raising the 2026-2028 covered conductor target from 440 to 775 circuit miles and lowering targeted undergrounding from 260 to 155 circuit miles.
