California Department of Resources Recycling and Recovery (CalRecycle) 

Conducting a Diversion Study: A Guide for Local Jurisdictions

Note: This page contains historical information from CalRecycle’s statewide goal measurement prior to 2007 that estimated a diversion percentage. For 2007 and subsequent years, CalRecycle compares reported disposal tons to population to calculate per capita disposal expressed in pounds/person/day. This new goal measurement system is described in the Goal Measurement: 2007 and Later web page. With the implementation of this measurement system, CalRecycle will only accept new base year studies commenced prior to June 30, 2008. A jurisdiction may conduct a generation study for internal review purposes; however, CalRecycle will not review it for compliance determination.


This diversion guide is a tool—not a policy document—to help jurisdictions properly identify changes in the waste stream since 1989. It will also allow jurisdictions to make adjustments in their diversion programs based on this information.

The California Department of Resources Recycling and Recovery (CalRecycle)recognizes that jurisdictions are unique in their makeup, with different demographics, waste streams, etc. Recognizing this uniqueness, CalRecycle has created a new base-year reporting tool so base-year studies can be presented and evaluated on a case-by-case basis. CalRecycle expects the following to be included in new base-year proposals:

  • Diversion study data submitted to CalRecycle must be properly documented and will require supporting documentation regarding existing programs that substantiate the proposed new base-year diversion rate.
  • While some activities are easier to quantify—e.g., tonnage records—other activities may require estimation. Thus, these activities will require a higher degree of substantiation, including detailing the methodology, assumptions, and other characteristics. They will also require a higher level of scrutiny by CalRecycle.
  • New base-year diversion rates must be representative of a jurisdiction’s diversion activities.
  • Any source reduction activities identified should be explained in detail in CalRecycle’s Base-Year Modification Certification sheet.

CalRecycle has continually affirmed that compliance with the Integrated Waste Management Act of 1989 (AB 939, Sher, Chapter 1095, Statutes of 1989, as amended) involves both achievement of the diversion mandates and implementation of diversion programs. CalRecycle is committed to ensuring that local governments are implementing the diversion programs described in their Source Reduction and Recycling Elements and their Household Hazardous Waste Elements. In upholding the intent of AB 939, CalRecycle also is expecting jurisdictions to demonstrate real disposal reduction and not to simply quantify preexisting diversion activities to reach the 50 percent diversion mandate.

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Last updated: September 8, 2009
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