Waste Audit 101: The Ins and Outs of Waste Auditing

Waste auditing has become a growing trend in waste management. But why do we do it and how does it work? Think Zero LLC recently conducted a webinar to answer these questions and more regarding this new strategy in achieving zero waste.


A waste audit is one of the first steps to creating an effective waste management plan. The goal is to find out what exactly is going into the trash and recycling within a specific building or company. The waste composition of a restaurant, for example, will be very different from that of a department store or office. The other objective is to figure out how many recyclables are ending up in the trash, and conversely, how much trash is mistakenly going into the recycling.


Waste audits must be conducted in the evening after all of the trash that accumulated during the day is brought down to the loading dock. Our team then spends about two hours auditing trash and two hours auditing recycling, sampling as many bags as possible in that time. Each bag is weighed, sorted to take out items that do not belong, and then weighed again. We also pull out single-use disposable items, such as plastic water bottles, plastic utensils, and take-out containers. From our experience, we have found it is best to take many pictures as well for further documentation.


Once the audit is complete, it is time to put all of the data collected to use. We calculate the total weight of both trash and recyclables before sorting and after sorting, and then find the contamination rate in each. This enables us to give the client their actual diversion rate and their potential diversion rate, that is, the percent of total waste they could divert from landfill if all recyclables were actually recycled. The potential diversion rate can also include food waste (also known as organics), which can be diverted from landfill by processing it via anaerobic digestion or turning it into compost. The single-use items are  counted to show the client where waste can easily be reduced. For example, if the team finds a large number of plastic water bottles in a client’s waste stream, we may suggest the client consider encouraging occupants to bring reusable bottles or install water refill stations.


With the insights gained from the waste audit data, we can create a waste management plan that most effectively targets the client’s areas of biggest opportunity and most in need of improvement. From there, we communicate our findings and recommendations through reports, face-to-face meetings, and presentations. The data is also used to craft customized signage, tip sheets, educational materials, employee training sessions, and more to resolve the issues uncovered by the audit. After the management plan has been fully implemented, our team conducts a second waste audit to gage whether not the goals have been met and to provide further recommendations if necessary.


We are always looking for people to help out with our waste audits throughout the year. If you are interested in participating, please contact Anna at asacks@thinkzero.com.