Every instruction booklet that comes with a dishwasher tells us to do this. Every repairperson who attends to a dishwasher mentions this at some point. And yet few people actually do it! If the water that goes to both your kitchen sink and the dishwasher is cold at the start the washer can’t get up to the proper cleaning and sanitizing temperature. Running the hot water in the sink until it’s actually hot takes care of this. It took me a while to remember to turn on the water every time, but it was worth it. Try it yourself for the next month and see if you notice the difference in how your detergent and spot removal agent work.