Scrape food instead of, or before, rinsing plates before putting them in the dishwasher
In a commercial kitchen, a low flow pre-rinse spray valve uses 5 litres of water per minute. If yours isn’t low flow it could be using as much as 20 litres per minute. In a staff room, the tap runs at 6 or more litres per minute. Of course, that rinse water is hot water, so energy is wasted as well. In a commercial kitchen, if you can cut your rinsing by 20%, you can save up to 30,000 litres of water per year.
By using a rubber scraper to remove food from plates, you can eliminate (or greatly reduce) the need to rinse dishes.