Cal. Code Regs. tit. 14 § 15152 : Natural Resources — Resources Agency — Guidelines for Implementation of the California Environmental Quality Act — Considerations in Preparing EIRs and Negative Declarations — Tiering

(a) "Tiering" refers to using the analysis of general matters contained in a broader EIR (such as one prepared for a general plan or policy statement) with later EIRs and negative declarations on narrower projects; incorporating by reference the general discussions from the broader EIR; and concentrating the later EIR or negative declaration solely on the issues specific to the later project.
(b) Agencies are encouraged to tier the environmental analyses which they prepare for separate but related projects including general plans, zoning changes, and development projects. This approach can eliminate repetitive discussions of the same issues and focus the later EIR or negative declaration on the actual issues ripe for decision at each level of environmental review. Tiering is appropriate when the sequence of analysis is from an EIR prepared for a general plan, policy, or program to an EIR or negative declaration for another plan, policy, or program of lesser scope, or to a site-specific EIR or negative declaration. Tiering does not excuse the lead agency from adequately analyzing reasonably foreseeable significant environmental effects of the project and does not justify deferring such analysis to a later tier EIR or negative declaration. However, the level of detail contained in a first tier EIR need not be greater than that of the program, plan, policy, or ordinance being analyzed.
(c) Where a lead agency is using the tiering process in connection with an EIR for a large-scale planning approval, such as a general plan or component thereof (e.g., an area plan or community plan), the development of detailed, site-specific information may not be feasible but can be deferred, in many instances, until such time as the lead agency prepares a future environmental document in connection with a project of a more limited geographical scale, as long as deferral does not prevent adequate identification of significant effects of the planning approval at hand.
(d) Where an EIR has been prepared and certified for a program, plan, policy, or ordinance consistent with the requirements of this section, any lead agency for a later project pursuant to or consistent with the program, plan, policy, or ordinance should limit the EIR or negative declaration on the later project to effects which:
(1) Were not examined as significant effects on the environment in the prior EIR; or
(2) Are susceptible to substantial reduction or avoidance by the choice of specific revisions in the project, by the imposition of conditions, or other means.
(e) Tiering under this section shall be limited to situations where the project is consistent with the general plan and zoning of the city or county in which the project is located, except that a project requiring a rezone to achieve or maintain conformity with a general plan may be subject to tiering.
(f) A later EIR shall be required when the initial study or other analysis finds that the later project may cause significant effects on the environment that were not adequately addressed in the prior EIR. A negative declaration shall be required when the provisions of Section 15070 are met.
(1) Where a lead agency determines that a cumulative effect has been adequately addressed in the prior EIR, that effect is not treated as significant for purposes of the later EIR or negative declaration, and need not be discussed in detail.
(2) When assessing whether there is a new significant cumulative effect, the lead agency shall consider whether the incremental effects of the project would be considerable when viewed in the context of past, present, and probable future projects. At this point, the question is not whether there is a significant cumulative impact, but whether the effects of the project are cumulatively considerable. For a discussion on how to assess whether project impacts are cumulatively considerable, see Section 15064(i).
(3) Significant environmental effects have been "adequately addressed" if the lead agency determines that:
(A) they have been mitigated or avoided as a result of the prior environmental impact report and findings adopted in connection with that prior environmental report; or
(B) they have been examined at a sufficient level of detail in the prior environmental impact report to enable those effects to be mitigated or avoided by site specific revisions, the imposition of conditions, or by other means in connection with the approval of the later project.
(g) When tiering is used, the later EIRs or negative declarations shall refer to the prior EIR and state where a copy of the prior EIR may be examined. The later EIR or negative declaration should state that the lead agency is using the tiering concept and that it is being tiered with the earlier EIR.
(h) The rules in this section govern tiering generally. Several other methods to streamline the environmental review process exist, which are governed by the more specific rules of those provisions. Where multiple methods may apply, lead agencies have discretion regarding which to use. These other methods include, but are not limited to, the following:
(1) General plan EIR (Section 15166 ).
(2) Staged EIR (Section 15167 ).
(3) Program EIR (Section 15168 ).
(4) Master EIR (Section 15175 ).
(5) Multiple-family residential development/residential and commercial or retail mixed-use development (Section 15179.5 ).
(6) Redevelopment project (Section 15180 ).
(7) Projects consistent with community plan, general plan, or zoning (Section 15183 ).
(8) Infill projects (Section 15183.3 ).

Cal. Code Regs. Tit. 14, § 15152

Note: Authority cited: Section 21083, Public Resources Code. Reference: Sections 21003, 21061, 21083.3, 21093, 21094, 21100, 21151, 21157 and 21158, Public Resources Code; Stanislaus Natural Heritage Project, Sierra Club v. County of Stanislaus (1996) 48 Cal.App.4th 182; Al Larson Boat Shop, Inc. v. Board of Harbor Commissioners (1993) 18 Cal.App. 4th 729; and Sierra Club v. County of Sonoma (1992) 6 Cal.App. 4th 1307.

1. Amendment of section and Note filed 10-26-98; operative 10-26-98 pursuant to Public Resources Code section 21087 (Register 98, No. 44).
2. Change without regulatory effect amending subsections (f)(3)(A)-(B) and repealing subsection (f)(3)(C) filed 7-22-2003 pursuant to section 100, title 1, California Code of Regulations (Register 2003, No. 30).
3. Change without regulatory effect repealing subsection (h)(7), renumbering subsections and amendingNote filed 10-6-2005 pursuant to section 100, title 1, California Code of Regulations (Register 2005, No. 40).
4. Amendment of subsection (h), new subsection (h)(8) and amendment of Note filed 12-28-2018; operative 12/28/2018 pursuant to Government Code section 11343.4(b)(3) (Register 2018, No. 52).