How to Perform a Waste Audit

Taken from:

Step-by-Step Waste Audit Instructions

Garbage is measured by how much it weighs and by how much space it takes up (volume). You’re going to estimate the volume and measure the weight of the materials you find in your school’s garbage cans.

Materials you will need:

• Rubber gloves.

• Clip board and garbage evaluation forms.

• Large tarp(s) to place sorted materials on.

• Large plastic bags to weigh garbage.

• Scale to weigh garbage.

• Five-gallon buckets (three or four).

Three easy steps:

Step 1: Choose the areas to evaluate and collect the garbage.

Collect the garbage at the end of the day and set it aside to audit the next day, unless you are doing the audit after school.

Step 2: Assign tasks.

If you are examining several areas, assign a team of students to each area. If you are examining only one area, give each student one of the evaluation tasks listed below:

Sorters: You need three to eight students to sort materials into categories.

Weighers: You need one to two students to weigh materials.

Recorders: You need one to two students to keep track of the weights and volumes.

Step 3: Do the Audit!

Carry the garbage you are evaluating to a place where you can sort the garbage on the tarp. The parking lot next to the dumpsters is best (if it’s not windy or raining).

• Weigh each can of garbage. Then dump out the garbage and weigh the can without the garbage. Subtract the weight of the empty can from the weight of the filled can. This gives you a total garbage weight.

• Now sort the garbage. Group materials into categories listed on the Waste Audit form. These material categories are a general guide. If you have very few of some items, you can combine them into categories such as paper, plastic, etc. If you find a lot of one item, such as paper bags or whole sandwiches, make that a separate category.


• When you’re done sorting, estimate the volume of each material. Volume is the amount of space the garbage takes up. Use five gallon buckets to estimate volumes. Pack the material slightly. Volume is important to know because it tells you what is “filling up” the school’s dumpster.

• Next, take each pile of sorted material and weigh it. Remember to subtract the weight of the bucket.

• Record the weight. If a bag doesn’t weigh enough to register on the scale, count the number of items. For example, a pile of plastic baggies won’t have any weight. Count them and write down the number of baggies you find. At the end of your evaluation, make sure your weights add up to the total garbage weighed. Your volumes should add up to the total gallons evaluated. The percentages of your weights and volumes should add up to 100 percent.

Waste auditing tips

• Every day is different when it comes to garbage. Make notes about things that could affect how much garbage is in the can. Are a lot of students absent today? Is it a “Clean Out Your Locker” day?

• As you sort and weigh materials, think about and discuss ideas for ways to reduce (or prevent), reuse or recycle the materials you find. Write down these ideas. They will come in handy when you write your plan of action. This could be a follow-up activity.