yeah, our small suburban house in silicon valley can easily use 400 gallons per day on days where we water the small front and back lawns and drip irrigation, but on a non-watering day, we can use as little as 50 gallons for 2 people.

While this is "a lot" of water, when we've had an irrigation leak in a zone that runs for 5 or 10 minutes, the number can balloon to 900 gallons in a day.

The amount of water used by people who actually don't closely monitor and track their usage, with big properties, lots of plants and lawn to irrigate, must be truly mind-boggling. I wouldn't be surprised if tens of thousands of gallons per day was pretty common at a lot of houses.