Environmental Impact Reports


The Lead Agency prepares environmental impact reports (EIRs) when a project may have a significant effect on our surroundings, such as toxic materials or possible air pollution. Environmental impact reports (EIRs) are, required by the California Environmental Quality Act (CEQA), and evaluates a proposed project’s impacts on the environment. The report also recommends steps to avoid or minimize those impacts, called mitigation measures. Potential alternatives to the project are considered as well, including the alternative of not doing the project.

Decision-Making Process

The public has an opportunity to review and provide comments on a draft of an EIR by contacting, in writing, the planner listed on the EIR. Public input is then included in the EIR, and considered by the decision-makers along with other aspects of the report. There may also be multiple meetings about the report, either as an item in a Planning Commission agenda or as a separate town meeting.

General Concepts

The information within an EIR allows the decision-making body (the Board of Supervisors, Planning Commission or City Council) to make an informed decision when considering whether or not to approve a project. The report also assists with deciding if approval conditions (entitlements) are necessary. The ultimate decision to approve a project, however, remains with the decision-making body. When the Board of Supervisors, Planning Commission or City Council approves an EIR, it is simply an acknowledgement that the EIR is precise and accurate. This is only one step towards project approval, and not a guarantee. The Board of Supervisors, Planning Commission or City Council may decide to instead decide to approve or deny the project based on overriding considerations.

Note: The approval of the environmental impact report does not mean that the project is approved. Once the report is approved, decision-makers review the project, taking into account the information in the report and other considerations.


  • The Planning Commissioner’s Handbook, League of California Cities, 2005, Chapter 4: The Planning Framework (www.ca-ilg.org/pch4)

  • State of California website on California Environmental Quality Act: http://ceres.ca.gov/ceqa/