Spring Water On Tap, an Atlanta-based startup company, is employing RFID to take water delivery service to a new level. The firm plans to install large tanks and employ wireless sensors coupled with tiny cellular modems, each carrying unique ID numbers, to track water levels in those tanks, thus ensuring that homes and businesses are never left high and dry. The solution will leverage ultrasonic sensors affixed to 65-gallon water tanks that will hold the water and be placed at homes and, potentially, businesses. The sensors--linked to cellular-based modems, also affixed to the tanks--transmit sonar signals down through the tank, measuring the return signal to discern water levels.
Source: RFID Journal, http://www.rfidjournal.com