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Understanding Waste Diversion

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In 1989, the Integrated Waste Management Act (AB 939) was passed and enacted Public Resources Code (PRC) section 41780, which required a 25% reduction of solid waste disposal by cities and counties by 1995 and 50% by 2000. The planning requisites in this section require waste diversion from landfill or transformation facilities through source reduction, recycling, and composting activities identified in city, county and regional agency Source Reduction and Recycling Elements (SRRE).

Under AB 939, diversion was calculated from a base year, where the State calculated: 1) how much waste was prevented (waste prevention), 2) how much waste was recycled and composted; and 3) how much waste was disposed.  The total of these three activities was considered the total waste generated. The total materials prevented, recycled and composted were considered diverted and the tons landfilled were not diverted. This was the process that was used to determine whether the City achieved the 50% diversion mandate.   

The City easily met the 1995 goal of 25% diversion, but meeting the 2000 goal was not as easy. In 2000, California’s waste reporting system was based on estimates of population, employment and taxable sales, not on the amount of trash disposed.  Due to a surging economy, high levels of business activity and construction, achieving a 50% diversion rate was more difficult for Davis.  Diversion rates did not include the tons of yard materials that were collected each week for composting by DWR—the State’s calculations did not consider these materials “diverted” using their reporting procedures. The City did achieve the State-calculated 50% diversion in 2001.

Sate-calculated waste diversion 1995-2006.

In 2007, SB 1016 was passed, changing the way the State measured waste diversion. The goal of the new per capita disposal measurement system was to make the AB 939 process of goal measurement simpler, timelier, and more accurate. SB 1016 changed to a disposal-based indicator—the per capita disposal rate—which uses only two factors: a jurisdiction's population (or in some cases employment) and its disposal as reported by disposal facilities. The AB 939 50% solid waste disposal reduction requirement is now measured in terms of per-capita disposal expressed as pounds of waste generated per person per day, or pounds per employee per day. The focus is on program implementation, actual recycling, and other diversion programs instead of estimated numbers.

Sate-calculated waste 2007-present.

It is often requested that the City’s diversion or per capita disposal rate be compared to other local agencies. However, it must be noted that CalRecycle itself strictly advises against such comparisons on their website:

  • Advisory! The per capita disposal rate is a jurisdiction-specific index and cannot be compared between jurisdictions. The per capita disposal rate is used as one of several "factors" in determining a jurisdiction's compliance with the intent of AB 939, and allows the California Department of Resources Recycling and Recovery (CalRecycle) and jurisdictions to set their primary focus on successful implementation of diversion programs. Meeting the disposal rate targets is not necessarily an indication of compliance. 

If a comparison must be done, the best way to compare one jurisdiction to another is to look at the waste generation. The tables and figures below compare the residential and employee waste generation per capita numbers of several jurisdictions.

The State of California took another step to increase diversion in 2011, when the governor signed AB 341, increasing the current State goal from 50% diversion to 75% recycling by 2020.  AB 341 created the Mandatory Commercial Recycling law, which requires that all businesses that generate four or more cubic yards of waste each week and all multi-family communities with five or more units must arrange for recycling service. Most Davis customers that fall under the Mandatory Commercial Recycling Law are already required to recycle under Chapter 32 of the Davis Municipal Code.  The few customers that do not are reviewed yearly by DWR and City staff for compliance.

City Of Davis Per Capita Residential Disposal

residential PPD

City Of Davis Per Capita Employment Disposal

employee PPD

City Of Davis Diversion


Comparison Of Residential Generation (Pounds/Person/Day)

waste generation chart

Comparison of 2011 Residential Generation (Pounds/Person/Day)


Comparison Of Employee Generation (Pounds/Person/Day)

waste generation chart

Comparison of 2011 Employee Generation (Pounds/Person/Day)