Author: Mario Fefee

The Regulatory Backdrop

Air quality modeling often requires assumptions about future motor vehicle emissions standards. However, these assumptions have been complicated by (1) the 2025 revocation of California’s Clean Air Act waivers, which previously allowed California to adopt motor vehicle emissions regulations on its own, and (2) the 2026 federal rescission of the GHG endangerment finding under the Clean Air Act. More specifically, in May 2025, the U.S. Senate approved several bills under the Congressional Review Act which purported to rescind California’s Clean Air Act waivers. (H.J.Res. 87, H.J.Res. 88, H.J.Res. 89.) The U.S. Senate Parliamentarian and the Government Accountability Office both concluded that the bills were illegal. California and other states also filed a lawsuit challenging the waiver revocations. (See State of California et al v. U.S.A. et al. (2025) N.D. Cal Case No. 25-CV-04966.) Furthermore, the 2026 administration rescinded the GHG endangerment finding and removed federal GHG motor vehicle emissions standards from 40 CFR part 600. (Vol. 90 Federal Register, No. 146, 36288.) This decision has been challenged in American Public Health Association, et al. v. United States Environmental Protection Agency and Lee Zeldin, Administrator, Case No. 26-1037 (D.C. Cir., filed Feb. 18, 2026). Consequently, there is substantial legal uncertainty about future motor vehicle emissions standards. Given this uncertainty, public agencies should be able to “make reasonable assumptions based on substantial evidence about future conditions without guaranteeing that those assumptions will remain true.” (Cal. Pub. Resources Code, §21080(e); City of Del Mar v. City of San Diego (1982) 133 Cal.App.3d 401, 412.)

CARB’s Response

In response to this regulatory uncertainty, in January 2026 the California Air Resources Board (CARB) revised the emissions factors for air quality modeling programs and released revised greenhouse gas (GHG) adjustment factors for EMFAC2021 to remove the estimated emissions benefits underlying ACT, Zero-Emission Airport Shuttle, Omnibus and Warranty Phase I regulations. These adjustment factors were developed for the EMFAC2021 model rather than the more recent EMFAC2025 model version as the use of EMFAC2025 might result in underestimating future emissions if the rescission remains, depending in part upon the outcome of these cases.

Related Case Law

Similar modeling issues have arisen in other CEQA cases, which may provide useful guidance in navigating this uncertainty:

• Planning and Conservation League v. Castaic Lake Water Agency (2009) 180 Cal.App.4th 210, 249
• Bay Area Citizens v. Association of Bay Area Governments (2016) 248 Cal.App.4th 966, 1017.)

Vallejo v. City of American Canyon (2026) 117 Cal.App.5th 1112

This case is a helpful guide for practitioners involved in the preparation of water supply analyses and the disclosure of water supply uncertainty.

The Court’s Analysis

Petitioner first asserted the WSA was inadequate for failing “to disclose amount of water actually purchased—as opposed to the amount of water available for purchase.” In rejecting this assertion, the Court reasoned the City has “historically received ‘100 percent of the full contracted volume’ of…permit water for all but one year.”

Petitioner next asserted the WSA failed to disclose “place of use restrictions” which it alleged violated CEQA’s requirements to discuss the uncertainty of the project’s water supply. The Court reasoned that this restriction did not fall within the restrictions identified under CEQA Guidelines Section 15155(f)(3) (i.e. “drought, salt-water intrusion, regulatory or contractual curtailments.”) The Court also reasoned “the place of use restrictions do not reduce the overall volume of water; they merely limit the areas within American Canyon that can receive that water.”

Finally, Petitioner alleged the WSA was inadequate for failing to address monthly curtailment during drought conditions in lieu of an annual analysis and “simultaneous curtailment” from the City’s different water providers. The Court rejected the first argument, explaining that nothing under CEQA or the water code mandated monthly analyses and that courts “cannot interpret the regulation to impose procedural or substantive requirements beyond those explicitly stated,” consistent with Pub. Res. Code §21083.1. The Court found the second argument meritless because the “EIR also discusses the possibility that water from either source might be curtailed, and supply reductions in Vallejo could lead to proportionate reductions.”

The Broader Trend

We’re seeing similar arguments being rejected by other courts, including one of the firm’s recent superior court wins defending the City of Seaside’s General Plan update and water supply analysis in Center for Biological Diversity v. City of Seaside (2025, Monterey Superior Court Case No. 24CV002483 [Rejecting the argument that General Plan EIR’s water supply analysis failed to discuss CBD’s Settlement Agreement with the Water Supplier which purported to limit “groundwater-sourced water supply” in the absence of developing new water supplies.])

The Bottom Line

These decisions confirm that agencies have meaningful flexibility in how they analyze water supply reliability under CEQA, so long as their conclusions are grounded in historical delivery data and a reasoned discussion of curtailment risk.

The Committee for Tiburon LLC v. Town of Tiburon (2026) 118 Cal.App.5th 259.

Why This Matters

This appellate decision may be one of the most interesting cases from 2026 for individuals preparing programmatic EIRs. The question presented to the Court was “if a local government is updating its general plan and housing element site inventory and no specific housing project has been proposed for a listed site, must the EIR for the general plan analyze site-specific environmental impacts of potential development of the site.” The Court concluded that no such analysis was required.

Background

The Town’s General Plan update included 17 potential sites that would accommodate the regional housing needs allocation. However, identification of these 17 sites did not mean development on any particular site was reasonably foreseeable. Housing Elements are generally required to provide “more residential units than the minimum number of units required by the RHNA to allow for a buffer.” After receiving comments on the suitability of Site H for Housing, the Town prepared additional studies of Site H’s constraints and traffic to demonstrate that it was suitable for redevelopment.

The Court’s Ruling

Petitioner sought to preserve Site H, a largely vacant nine acre parcel, which would be allowed to build up to 118 units under the updated plan. Petitioner asserted that site specific analysis of Site H should have occurred because (1) the additional Site H studies made site specific review feasible, and (2) “if no site-specific environmental review for Site H is included in this EIR, then such analysis will never be included [due to potential use of statutory housing exemptions].” The Court rejected both arguments, first reasoning that “without a proposed project that identifies critical factors such as the amount and configuration of the proposed housing…the Town can only speculate as to the severity of any particular environmental impact.” Secondly, the Court reasoned that “the possibility that a future housing project may qualify for a CEQA exemption does not, by itself, make site-specific impacts more feasible to analyze at the general plan and housing element stage.”

The Broader Trend

This second argument appears to be arising more often in CEQA litigation involving long range plans. This might be attributable to increased statewide policies which are making more developments ministerial and exempt from CEQA. For example, in Sacramentans for Fair Planning v. City of Sacramento (2019) 37 Cal.App.5th 698 Petitioner faulted the city’s environmental analysis, alleging that the programmatic analysis did not identify “residential densities and building intensities within the region to the extent necessary to enable a project’s significant effects to be mitigated, and thus it cannot form the basis for justifying streamlined CEQA review.” The Court rejected this assertion, reasoning “Plaintiff’s concern that some type of environmental review may not occur by using an SCEA in this instance is a complaint to take to the Legislature…If it chose to exempt certain types of development from full environmental review based on those rational bases, we are not at liberty to question their wisdom.”

However, such exemptions are not strictly limited to those adopted by the legislature. Similar issues also arose in San Diego Citizenry Group v. County of San Diego (2013) 219 Cal.App.4th 1, where the County adopted “regulatory amendments streamlining the winery approval process and allowing small boutique wineries ‘by right.’” Petitioner alleged the county violated CEQA by eliminating its discretionary process “which allowed by-right use without further discretionary review,” “[Petitioner] claims this is a ‘uniquely problematic’ case because boutique wineries will be allowed by right and thus without further mitigation.” In rejecting such assertions, the Court reasoned “CEQA does not, indeed cannot, guarantee that [an agency’s] decisions will always be those which favor environmental considerations,” and upheld the agency’s policy decision “given the Project objectives of encouraging the growth of agriculture and the wine industry by streamlining.”

The Bottom Line

Practitioners preparing programmatic EIRs for general plans and housing elements should take note: courts continue to reject arguments that plan-level review must analyze site-specific impacts merely because more detailed studies could theoretically be developed, or because future ministerial approvals might otherwise escape CEQA review altogether.

Bair v. California Department of Transportation (2026) 119 Cal.App.5th 579

Why This Matters

This decision offers important guidance on how claim preclusion doctrines apply to successive CEQA challenges arising from the same project, and reflects the courts’ growing impatience with serial litigation strategies.

Background

Bair is the third lawsuit over the last 15 years which challenged a highway project through an old-growth redwood grove which would reconfigure an existing 1 mile stretch in Humboldt County. This litigation may be familiar to some readers, as the prior published appellate decision faulted Caltrans’ EIR for failing to disclose the project’s pre-mitigation impact conclusions regarding the redwood trees and relying upon a non-regulatory handbook to conclude impacts were less than significant. (Lotus v. Department of Transportation (2014) 223 Cal.App.4th 645.) The second lawsuit involved a successful procedural challenge to an Addendum which attempted to fix the substantive deficiencies in the prior EIR. However, this second lawsuit did not address the substantive analysis in the Addendum. In response to these losses, Caltrans circulated the previous EIR and pre-existing Addendum for public review unchanged, and reapproved the project in 2023. Caltrans then sought discharge of the writ from the prior case.

The Court’s Ruling

This third case at issue in Bair involved a simultaneous challenge on the discharge of the writ from the prior case and a new independent lawsuit. Petitioner faulted Caltrans’ substantive analysis of biological impacts to the old-growth redwood trees. The Court of Appeal ruled that Petitioner’s third lawsuit was barred by res judicata/claim preclusion, which bars litigation not only of issues that were actually raised in the prior case, but those that could have been raised, but were not. In assessing the preclusive effect of the prior litigation, the court noted that the central question was “whether the revised EIR’s compliance with CEQA could have been adjudicated in response to the [agency’s] post judgment request to discharge the writ.” The Court reasoned that Petitioner could have appealed the ruling in the original Lotus case if they believed that the court erred, but they did not do so. In clarifying the standard for applicability of claim preclusion, the Court of Appeal disagreed with the reasoning in Central Delta Water Agency v. Department of Water Resources (2021) 69 Cal.App.5th 170.

The Bigger Picture

In a growing trend among CEQA cases, the Court lamented that CEQA is more often being used as “a never-ending battle…that can drag on for years, even decades.” Similar concerns were raised in Tiburon Open Space Committee v. County of Marin (2022) 78 Cal.App.5th 700, 781-783; Citizens of Goleta Valley v. Board of Supervisors (1990) 52 Cal.3d 553, 576 [“we caution that rules regulating the protection of the environment must not be subverted into an instrument for the oppression and delay of social, economic or recreational development and advancement.”]; County of Orange v. Superior Court (2003) 113 Cal.App.4th 1, 6 [“[t]he Legislature has obviously structured the legal process for a CEQA challenge to be speedy, so as to prevent it from degenerating into a guerilla war of attrition by which project opponents wear out project proponents.”].  While this might not be a legal basis for seeking dismissal of a CEQA case, practitioners may wish to incorporate similar themes into their briefing.

What to Watch

Readers should be aware that a request to de-publish this opinion was filed on May 26, 2026, which had not been addressed yet by the Supreme Court as of July 14, 2026.