Re: Cold water requirement. It's not as ridiculous as it may seem. --In the 70's, we were told (in the US) to not flush the toilet after peeing. --We also were told that driving at 55mph was the optimum, most fuel efficient speed for all vehicles under all circumstances. --In the 2000's, my kids were urged to watchdog our family so that we didn't leave the tap on for more than 10 seconds while brushing our teeth. --In the 2010's, light bulbs that emit warm tones of light were apparently outlawed to save energy. I could see cold water becoming a thing.