When grabbing a cup of coffee in the staff lounge or at a training session, there is much debate on whether a a reusable mug is better for the environment than a disposable mug. Its takes energy, water, etc. to clean a reusable mug and some argue it is a negative impact to the environment. A 1994 study from the ILEA discussed these ideas if you want to check it out and make your own decision.
But if you have a large staff of people who will use reusable mugs, an energy efficient dishwasher, and don’t pre-rinse or use the heat dry cycle, it is better to reuse your mugs by cleaning them in a full dishwasher.
A great example: I use to attend training sessions at New Horizons Computer Learning Center in Colorado. They might have 4-8 rooms of 10-40 people each doing trainings on the same day. Yet their lounge had all reusable mugs for hot drinks. They had a dishwasher and easily filled it to run daily. For once, I didn’t have to bring my own reusable travel mug 🙂