The problem is that many coffee shops and ice cream parlors leave their dipper wells on regardless of how much business they're doing. That means water is constantly flowing, and it adds up very quickly. As restaurants explore sustainable and environmentally friendly practices, partly out of personal conviction, partly out of the need to cut costs, and mainly because customers are demanding it, things like the dipper well have become more and more obsolete.
Dipper wells became so ubiquitous because of food safety concerns. A constant flow of water helps prevent bacterial buildup, and they are so easy to clean and use that even the greenest employee can be put to work while minimizing contamination problems. Plenty of other methods address the food safety issue and are almost as easy to implement, however.
Besides the ethical issue of wasting a precious resource like potable water, dipper wells are also a drag on any business' bottom line. It's a deceivingly large monthly expense that's easy to miss since your water bill also includes dishwashing, food prep, beverages, ice, etc. Depending on how many dipper wells you use, turning them off could add up to several hundred dollars a year once you account for water and wastewater charges.
What are some alternatives to dipper wells? Starbucks has started using a one scoop, one pitcher policy in some stores, meaning the scoop and pitcher are used once before being washed. A commercial undercounter dishwasher could easily replace a dipper well and significantly reduce water usage since many models use less than a gallon per rack.