CEQA vs. NEPA comes down to which government is approving your project: the California Environmental Quality Act applies when a California state or local agency exercises discretion over a project, while the National Environmental Policy Act applies when a federal agency takes a major action significantly affecting the environment. Many large projects trigger both and go through a combined review. The two laws look similar on the surface, but CEQA can force an agency to actually reduce a project’s impacts, while NEPA generally only requires the federal agency to study and disclose them.
Which Law Applies to Your Project
CEQA covers any discretionary project a California public agency carries out or approves. That includes issuing permits, changing zoning, approving subdivision maps, and spending public funds on construction. The word that matters is “discretionary”: if an official exercises judgment about whether to approve something rather than following a fixed checklist, CEQA applies.1California Natural Resources Agency. California Public Resources Code 21080 – Division Application to Discretionary Projects
NEPA kicks in when a federal agency takes a “major federal action significantly affecting the quality of the human environment.” In practice, that means projects funded by federal grants, requiring federal permits, or built on federal land. A new interstate highway segment, a dam on navigable waters, or a pipeline crossing federal property all trigger NEPA review.2Office of the Law Revision Counsel. 42 USC 4332 – Cooperation of Agencies; Reports; Availability of Information
A single project often hits both thresholds. A light rail extension that uses federal transit funds but needs a local land use permit will need to satisfy both laws. Neither one preempts the other.
The Core Difference: Substance vs. Procedure
This is the practical heart of the comparison. CEQA imposes a substantive obligation on California agencies: where feasible, they must actually mitigate or avoid significant environmental impacts, not just acknowledge them. NEPA is traditionally treated as a procedural law. A federal agency must disclose and consider environmental effects, but it can still approve a project with significant unmitigated impacts as long as it explains the choice.
For a community group fighting a project, that difference is enormous. Under CEQA, pointing out a feasible mitigation measure the agency ignored can force design changes. Under NEPA, the same showing may force more analysis, not a different outcome.
The Documents Each Process Produces
Both laws use a tiered system. A preliminary screening decides whether a project needs no document, a short one, or a full study.
CEQA
Review starts with an Initial Study. If it finds no significant impacts, the agency adopts a Negative Declaration. If impacts exist but the applicant agrees to design changes or conditions that reduce them below significance, the agency adopts a Mitigated Negative Declaration. If significant impacts remain, the agency must prepare a full Environmental Impact Report (EIR), the most detailed CEQA document, covering every significant effect, feasible alternatives, and mitigation measures.3Governor’s Office of Planning and Research. CEQA 101
Some projects skip the process entirely under categorical exemptions for routine activities like minor maintenance or small-scale construction, though exemptions fall away in unusual circumstances or where historical or hazardous waste resources are involved.4Legal Information Institute. California Code of Regulations Title 14 Section 15300 – Categorical Exemptions The legislature has layered on statutory exemptions for infill housing, affordable housing, and certain emergency shelters.5Governor’s Office of Land Use and Climate Innovation. Site Check and Other CEQA Housing Resources
NEPA
The federal structure mirrors it. An Environmental Assessment (EA) is the screening document. If the EA concludes impacts will not be significant, the agency issues a Finding of No Significant Impact (FONSI). If impacts are likely significant, the agency prepares a full Environmental Impact Statement (EIS), concluding with a Record of Decision (ROD) explaining the chosen alternative, the environmentally preferable alternative, and whether all practicable mitigation was adopted.6eCFR. 40 CFR 1505.2 – Record of Decision Each federal agency keeps its own list of categorical exclusions for routine actions that normally skip EA and EIS review.7eCFR. 40 CFR 1501.4 – Categorical Exclusions
How the Documents Line Up
- Initial Study ↔ Environmental Assessment
- Negative Declaration / Mitigated Negative Declaration ↔ Finding of No Significant Impact
- Environmental Impact Report ↔ Environmental Impact Statement
- Notice of Determination ↔ Record of Decision
Alternatives: The Most Contested Section
Both laws require a serious look at alternatives. Under NEPA, the alternatives section is treated as “the heart of the environmental impact statement,” and an EIS must evaluate a reasonable range of options plus a no-action alternative.8eCFR. 40 CFR 1502.14 – Alternatives Including the Proposed Action CEQA uses a “rule of reason”: an EIR must cover a range of feasible alternatives that could meet most of the project’s objectives while reducing significant impacts, usually including a reduced-scale option, an alternative site, and a no-project option.9Legal Information Institute. California Code of Regulations Title 14 Section 15126.6 – Alternatives to the Proposed Project
Public Comment Windows
Both laws build in formal public comment at several stages, and the agency must respond to the substance of what people submit. The minimum timelines are not symmetrical.
Under CEQA:
- Proposed Negative Declaration or Mitigated Negative Declaration: at least 20 days, extended to 30 days when the document goes to the State Clearinghouse because a state agency has jurisdiction.10Legal Information Institute. California Code of Regulations Title 14 Section 15073 – Public Review of a Proposed Negative Declaration or Mitigated Negative Declaration
- Draft EIR: at least 30 days, extended to at least 45 days when submitted to the State Clearinghouse.
- Scoping for an EIR begins with a Notice of Preparation; responsible agencies have 30 days to weigh in on issues and alternatives.11Legal Information Institute. California Code of Regulations Title 14 Section 15082 – Notice of Preparation
Under NEPA:
- A draft EIS carries a minimum 45-day public comment period.12Environmental Protection Agency. National Environmental Policy Act Review Process
- Scoping begins when the agency publishes a Notice of Intent in the Federal Register.
When Both Laws Apply at Once
Projects that trigger both laws do not need two parallel reviews. Federal regulations encourage integrating NEPA with state reviews like CEQA, and agencies routinely prepare a joint EIR/EIS that addresses both legal standards in one document.13Council on Environmental Quality. NEPA CEQA Handbook The lead state and federal agencies typically sign a written agreement allocating research tasks, data sharing, and timeline. The payoff is one administrative record and one document for the public to actually read.
Federal Page and Time Caps That CEQA Does Not Have
NEPA regulations cap an EIS at 150 pages for most projects, or 300 pages for proposals of unusual scope or complexity, not counting appendices. EAs are capped at 75 pages.14U.S. Government Publishing Office. 40 CFR Part 1502 – Environmental Impact Statement The Fiscal Responsibility Act of 2023 added time limits: two years for an EIS, one year for an EA. Before those deadlines took effect, the average time to complete a federal EIS was about 4.5 years, so whether agencies will consistently hit two years on complex infrastructure is still an open question.
CEQA has no equivalent statutory page or time caps. California EIRs sometimes run thousands of pages and take several years to finalize.
Deadlines to Sue
If you want to challenge a project in court, the window under CEQA is unusually short, and missing it forfeits the challenge entirely. The clock depends on what notice the agency filed:
- 30 days from the filing of a Notice of Determination to challenge the adequacy of an EIR, the propriety of a Negative Declaration, or other CEQA compliance issues.
- 35 days from the filing of a Notice of Exemption to challenge an exemption determination.
- 180 days from the agency’s decision if no notice was filed, or from commencement of the project if no formal decision was made.
These periods are set out in California Public Resources Code Section 21167.15California Legislative Information. California Public Resources Code 21167 The usual remedy is a writ of mandate ordering the agency to set aside its approval and redo the environmental review, and courts can enjoin construction while the agency fixes the problem.16Legal Information Institute. California Code of Regulations Title 14 Section 15112 – Statutes of Limitations
NEPA challenges are filed in federal court under the Administrative Procedure Act and generally face a six-year statute of limitations, though some agencies set shorter review windows by regulation. The practical result: NEPA projects carry a far longer window of legal exposure than CEQA projects.
Choosing Where to Focus
If you are a project applicant, the question is which approvals you need and from whom. Local permit? CEQA. Federal permit, funding, or land? NEPA. Both? Plan on a joint document and build the longer federal timeline into your schedule.
If you are a neighbor, community group, or tribe trying to influence or stop a project, the leverage points differ. On the CEQA side, your strongest tools are demanding feasible mitigation and watching the 30-day clock after the Notice of Determination posts. On the NEPA side, you have more time to sue, but a win usually means better disclosure rather than a redesigned project.