CEQA glossary

Initial Study

A plain-language definition of an Initial Study, its role in choosing or focusing the next CEQA document, and the evidence its entries require.

An Initial Study is a preliminary analysis prepared by a lead agency to decide whether an environmental impact report or negative declaration must be prepared, or to identify the environmental effects that need analysis in an environmental impact report.

Why an Initial Study matters

An Initial Study gives the lead agency information for deciding which CEQA document to prepare and can help focus a later environmental impact report. CEQA Guidelines section 15063 says it briefly identifies the project and location, environmental setting, environmental effects, possible mitigation for identified significant effects, consistency with applicable land use controls, and the people who prepared or participated in the study.

A lead agency may use Appendix G as part of the format, but Appendix G is suggested rather than mandatory. Checklist entries must be briefly explained and supported by evidence or a cited information source.

What an Initial Study does not establish

A public-database result, map, or unchecked source list is not an Initial Study by itself. The document requires the lead agency’s project-specific review and independent judgment. A draft prepared for the agency does not replace that responsibility.

The term also does not tell you in advance which CEQA document the project will require. That decision follows the applicable review and evidence.

Primary source

CEQA Guidelines section 15365 defines “Initial Study.” CEQA Guidelines section 15063 describes its use, purposes, contents, and possible formats. The official California Code of Regulations pages were current through August 28, 2026, Register 2026, No. 35, and were accessed September 10, 2026.

Published 2026-09-10 · Last materially reviewed 2026-09-10