The California Air Resources Board (CARB) is about to release the revised and final version of the Advanced Clean Fleets (ACF) regulatory amendments. The last time the California Association of Sanitation Agencies (CASA) published an article on this topic (May 2024), CASA had just begun working with CARB and its staff to amend the ACF into a workable regulation by incorporating requirements of Assembly Bill 1594 (Garcia). In the absence of viable zero-emission vehicle (ZEV) options, AB 1594 authorizes public water, wastewater, and power agencies to purchase traditional (medium- and heavy-duty) vehicles as replacements when a vehicle reaches the end of its useful life (regardless of its age) in order to maintain reliable service and remain responsive in emergencies.
As we entered January 2025, discussions with CARB continued, and changes in the federal administration led to a shift away from supporting of ZEVs (battery-electric or hydrogen fuel cell vehicles). CARB had not yet received approval for its waiver of preemption request from the Environmental Protection Agency (EPA), which would have allowed it to implement the ACF Regulation in full. As a result of the change, CARB decided to withdraw the request prior to inauguration day, knowing the new administration would have likely declined it. While this means CARB does not have authority to enforce the ACF regulations on private and drayage medium- and heavy-duty vehicles (i.e., vehicles with a gross vehicle weight rating greater than 8,500 pounds), they maintained they had authority over State and Local Government Agency Fleets (Section 2013) and would continue to regulate those vehicles.
Notably, the State and Local Government Agency Fleets account for less than 7% of medium- and heavy-duty vehicles statewide. However, CARB stated that their other regulations (specifically, the Advanced Clean Trucks Regulation and the Heavy-Duty Omnibus Rule), in combination with the Clean Truck Partnership Agreement, create enough market demand for truck manufacturers to produce the needed vehicles.
Five months later, on June 12, 2025, the House and Senate voted to use the Congressional Review Act (CRA) to disapprove of three waivers of preemption that were previously approved by the EPA, allowing CARB to regulate passenger vehicles to heavy-duty vehicles – even though the Government Accountability Office determined the CRA could not be applied to EPA-approved waivers. The President subsequently signed Resolutions 87, 88, and 89, rolling back the Advanced Clean Trucks Regulation, the Advanced Clean Cars II Regulation, and the Heavy-Duty Omnibus Rule, respectively. Not long after that, the Federal Trade Commission secured commitments from manufacturers stating that the Clean Truck Partnership Agreement was no longer enforceable.
On the same day the President signed the Resolutions, Governor Newsom issued Executive Order N-27-25 – reaffirming California’s commitment in Executive Order N-79-20. The state, in effect, doubled down on transitioning vehicles (from passenger vehicles to heavy-duty trucks) to zero-emission technologies by requiring that all sales of new vehicles must be ZEV by 2035 and all medium- and heavy-duty vehicles in the state must be ZEV by 2045. These targets are designed to achieve carbon neutrality by 2045 and meet ozone standards in various air basins.
In the wake of various federal actions designed to unravel California’s clean vehicle mandates and the Clean Truck Partnership Agreement, State and Local Government Agency Fleets began to fully understand the burden being placed on them and the highly uncertain future associated with the manufacturing of ZEVs. These concerns were raised with CARB on numerous occasions. However, CARB decided to continue moving forward with implementing California’s ACF to transition a subset (less than 7% of medium- and heavy-duty) of vehicles to ZEVs, which are responsible for ensuring services considered to be critical functions in the protection of public health and the environment.
In fact, as essential public service providers of water supply and the collection and treatment of wastewater 24 hours per day, 365 days per year, the National Coordinator for the Critical Infrastructure Security & Resilience and Department of Homeland Security designated these as National Critical Functions. In other words, their disruption, corruption, or dysfunction would have debilitating effects on state and national security, economic stability, and public health and safety.
Furthermore, public agencies serve as second responders in emergencies, recovering community services alongside first responders in events such as heavy rain, snow, flooding, fire, mudslides, earthquakes, and other disasters. In some cases, public agencies also serve as first responders. These roles were established under California’s Disaster and Civil Defense Master Mutual Aid Agreement to ensure communities had the means to perform duties to prevent and respond to emergencies.
In the wake of a much narrowd scope of state regulatory action and the current federal approach to ZEVs, a key question remains – will a ZEV market exist to only serve State and Local Government Agency Fleets? We recently got a glimpse of how this market may change in the future. From June to December 2025, ZEV truck manufacturers began announcing changes in their production. On December 15, 2025, Ford announced it was halting production of the F-150 Lightning immediately due to low demand for battery-electric vehicles (BEVs). In January 2026, General Motors announced it would scale back production of its truck BEVs and pivot to hybrid models. The remaining Class 2b/3 ZEV truck CARB has approved is the Rivian, which is a luxury vehicle of unibody construction, and does not allow for the needed modifications and upfitting required for utility operations.
Challenges with hydrogen fuel cell vehicles (HFCV) have also begun to surface, revealing that HFCV fleets are struggling to maintain market demand due to technical issues at fueling stations, high expenses, and safety issues at their storage and handling sites. Notably, only a portion (at times as low as 30%) of California’s hydrogen fueling stations are open at any given time. Each of these factors represents a level of risk that is not tolerable for State and Local Government Agency Fleets responsible for ensuring national critical functions. When combining these factors, it becomes clear that State and Local Government Agency fleets need flexibility and access to exemptions built into the ACF regulations for them to maintain reliable services.
CASA and its members have been advocating alongside the Association of California Water Agencies and the California Municipal Utilities Association since the adoption of the ACF regulations. Our collective goal is to not only allow earlier access to exemptions, but to also provide access to vehicles that are capable of providing the types of operations and functions needed while also emitting low to ultra-low levels of oxides of nitrogen (NOx) and greenhouse gases (GHG). This approach can help achieve CARB’s objectives without endangering public health and the environment. Fleets across the state have discovered that ZEVs available today are not functionally equivalent to traditional vehicles and come at a high cost to ratepayers. In some cases, the battery capacity tested at typical demand levels can last only 55 minutes, when some crews need to be on-site for 12 to 16 hours in a single day.
As one example of how this plays out in the real world, a winter storm in February 2026 required the Calaveras County Water District (CCWD) to deploy 50% of its fleet to maintain water supply and prevent inflow and infiltration from overwhelming sewer systems to avoid sewer backups and spills. Power in their largest service territory was out for several days, and up to 10 days in some locations. Their trucks served as warming centers, offices, quiet spaces, and dinner tables while crews were working 12- to 16-hour days. The CCWD crews assisted in the rescue of many individuals as well, serving as first responders. There are no ZEVs on the market that can provide that level of service for the duration required, nor are there any anticipated in the near future.
It is also important to consider whether an increased reliance on ZEVS is supportable by our current electrical infrastructure. We have been connecting with power utilities to understand their outlook on future capacity for supporting the increased demand related to residential passenger and light-duty vehicle electrification, implementation of data centers, and eventually medium- to heavy-duty vehicle electrification when those ZEVs become available. We have learned (perhaps unsurprisingly) that data center implementation is outpacing the development of the electrical grid. Pacific Gas & Electric (PG&E), the state’s largest utility, shared with regulators in 2025 that data center projects could add 10 gigawatts of electricity demand over the next decade — approximately four times the generating capacity of the Diablo Canyon nuclear plant. For additional context, the Sacramento region uses just over 3 gigawatts of electricity at its busiest times. This reality calls into question whether the grid is prepared for increased demand from a much larger number of ZEVS in the coming decade.
State and Local Government Agencies provide services essential to protecting public health and the environment every day, all day long, all year, and cannot be put at risk of disruption. Therefore, regulations need to allow for these types of facilities (and their fleets) to deliver on those services, avoiding debilitating effects on state security, economic stability, and public health and safety.
This brings us to today, and what we are asking CARB to consider in its final round of amendments to the ACF regulations. Taking all the above into consideration, our role as essential public service providers of critical functions, and the fact that we do not see viable medium- and heavy-duty ZEVs that provide the level of performance needed becoming available any time soon, we have two core needs:
Allow public agencies access to a low-NOx internal combustion engine (ICE) vehicle in both the Purchase Schedule and Milestone Option compliance pathways of the ACF regulations. The technology exists today and is implementable by public agency fleets.
Allow public agencies the ability to fuel their Low-NOx ICE vehicles with renewable biomethane, to achieve GHG emissions reductions while ensuring the resilience of essential services, and securing a long-term use for renewable biomethane, which is a natural byproduct of wastewater treatment, establishing a circular economy.
Public agencies can still support CARB’s goal of reducing emissions in the coming decade and fulfilling our role of protecting critical functions at the same time. Unfortunately, the ACF regulations, as they are currently structured, are not feasible, achievable, and could ultimately threaten our role as protectors of public health and the environment.
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