CVSan has completed nine years of waste audits in Castro Valley schools!  A waste audit identifies the type of material going into the garbage that could have been recycled or composted.  For example, we find paper and plastic in the garbage that could have been recycled in the blue bin.  It’s important to remember that garbage travels directly to the landfill.  Waste audits are an exciting learning activity for students, teachers, and parent volunteers to see firsthand what else can be recycled or composted instead of going to the landfill.  Please read on to learn more about our excellent School Waste Audit program and how to sign-up your Castro Valley school today.

Shown above, the Castro Valley High School Waste Audit on February 23, 2019.

In the 2018/19 school year, 16 public and private schools participated in waste audits.  Students, teachers, and parent volunteers sorted through one day’s worth of garbage from their entire campus.  CVSan compiled the results and provided each school with a report on what was found in the garbage and strategies on how to reduce waste.  CVSan also presents results to School District Administrators once a year. 

Waste Audits are quickly becoming an instrumental tool to encourage improvements in waste reduction programs at schools.  For example, data from all 16 waste audits demonstrated that despite existing school recycling programs in classrooms and lunchtime, the percentage of recyclables based on volume (paper, plastic, metal, glass) found in the garbage was still 54%.

Waste Audit Data & Improvements
For waste audit improvements, this is one time we want to see the garbage figure increase.  We want to find “actual garbage” in the garbage.  The “actual garbage” found in the garbage data is most telling of progress made and therefore how much work can still be done when coupled with the percentage of recycling and organics in the garbage.  In the past five years of the waste audit program, the average garbage found in the garbage has increased from 27% in 2010/11 to 46% in 2018/19.  This is a trend we want to see continue!  CVSan also found the organics material found in the garbage has decreased over time from 42% in 2010/11 to 27% in 2018/19.  This is evidence of improvements in food scrap recycling at many schools.  Great job Castro Valley schools!

2018/19 Average Waste Audits Results:

Chart B: Average percentage of organics, recycling, and garbage sorted from the garbage at all participating elementary, middle, and high schools by volume


Waste audits for 2019/20 are now being scheduled for the period of November 2019 through February 2020.  Contact or (510) 537-0757 to schedule your waste audit. Together you will select the appropriate day for the “School Waste Audit Day.”  We recommend performing the waste audit in the morning and anticipate it will take approximately 45 minutes – 2 hours, depending on the amount of garbage being sorted.  During the Waste Audits, 10 students and two parent volunteers from your school along with CVSan staff will sort one day’s worth of garbage to determine what could have been recycled or composted.  Waste Audits are mandatory for all 2019/20 Green Ribbon Schools. 

Tip: Avoid scheduling the waste audit after an event at the school, after a minimum school day, or during field trips.  These "special circumstances" will misrepresent the waste generated at your school. 

Other CVSan School Programs: 

3rd Grade 4Rs Field Trip

Green Ribbon Schools Program

Schools Food Scrap Recycling Program