California Code of Regulations
Title 25 - Housing and Community Development
Division 1 - Housing and Community Development
Chapter 6.5 - Program Operations
Subchapter 3 - California Environmental Quality Act
Article 6 - Criteria for Decision-Making and Findings
Section 6990 - Determining Significant Effect

(a) The determination of whether a project may have a significant effect on the environment calls for careful judgment based on available data. An ironclad definition of "significant effect" is not possible because the significance of an activity may vary with the setting. For example, an activity which may not be significant in an urban area may be significant in a rural area. Where there is, or there is anticipated to be, a substantial body of opinion that considers the effect to be adverse, the Lead Agency should prepare an EIR to explore the environmental effects involved.

(b) In evaluating the significance of the environmental effect of a project, the Lead Agency shall consider both primary or direct and secondary or indirect consequences. Primary consequences are immediately related to the project (the construction of a new treatment plant may facilitate population growth in a particular area), while secondary consequences are related more to primary consequences than to the project itself (an impact upon the resource base, including land, air, water and energy use of the area in question may result from the population growth).

(c) Some examples of consequences which may be deemed to be a significant effect on the environment are contained in Appendix E.