When the Metropolitan Water District of Southern California this week unveiled its strictest-ever water restrictions for about 6 million residents, it did so with an urgent goal in mind: a 35% reduction in water consumption, equating to an allocation of about 80 gallons per person per day.

Officials said that’s the number needed to conserve critical supplies for health and safety amid worsening drought — and to prevent a full outdoor watering ban as soon as September. Currently, the average potable water use across the MWD’s service area — including residential, commercial and industrial water use — amounts to 125 gallons per person per day.