Water is on the minds of Rockland residents this summer, and not just because of the record U.S. drought. Rockland County’s main water provider, United Water NY, wants to build a treatment plant on the Hudson River that would deliver more freshwater to Rockland taps. Some people are in favor of boosting supply to this growing suburban region, a short drive from the George Washington and Tappan Zee bridges. Others are opposed, citing the cost, in energy and dollars, plus the danger to fish and other wildlife. As the project awaits approval from the state Department of Environmental Conservation, a new debate on water consumption has emerged. Should people be encouraged, or even required, to use less? And if so, how?