A preliminary discussion about Carson City water service and sewer treatment fee increases left Mayor Robert Crowell skeptical about relying solely on fees.Crowell, after a staff presentation to the Board of Supervisors Thursday about projected multiyear fee hikes to cope with aging sewer treatment plant problems, urged consideration of an eighth-cent sales tax hike.“Why isn't that in the mix?” he asked. He made the point that tourists flush toilets in Carson City, not just residents. Crowell and supervisors were reacting to fee hike ideas projected at 3 percent annually on water, 10 percent on sewer service. The discussion was part …