Water Cost The Carlsbad Desalination Plant in California that is being built estimates that their water cost will be $2,131 to $2,367 per acre-foot in 2016, depending on how much is purchased annually.  An acre-foot is equal to 325,851 gallons of water, thus each gallon will cost about $0.0073.  The cost for water per each traveler will be about $0.044. This does not take into consideration the pumping of the sea water to the desalination plants that will be located at the various stations along the BorderTransportationSystem route.  It does not take into consideration the chlorine cost, or the cost of processing the waste products, i.e., Graywater.  See Funding of the system Water use for industrial, commercial, and farming use. The water for these uses will have a premium add-on for its use based on a sliding scale that increases the cost per 1,000 gallons over a daily limit.  This is to help conserve water, and is 100% different than what many Public Water Utilities do.  Index of ...