Two things are true about the cost of water in San Diego: the cost of bringing water here and maintaining the system that does it is rising, but the amount of water San Diegans consume is dropping.  In 1990, the average San Diegan used 235 gallons of drinkable water per day, according to the Water Authority’s records. By 2021, San Diegans cut that almost in half to 130 gallons per day. Megadroughts that triggered mandatory water cutbacks triggered better water conservation habits, which stuck.