The history of odd/even day watering restrictions

Reading Alex Breitler’s story yesterday about Stockton, for the first time in history, restricting the days of the week residents can water their lawns, I was reminded of this bit of business from Las Vegas:

In 1950, the municipality began restricting lawn watering. During the next two years the city employed the alternate day method, allowing homeowners with lots facing north and east to water their grass on even-numbered days of the month and the rest on odd.

That’s from Eugene P. Moehring’s Resort City in the Sunbelt, Las Vegas, 1930-2000. I’ve been unable to figure out how to confirm whether that’s the first example of odd-even watering. If anyone knows some bright grad student who’s done “The History of Municipal Water Conservation Policy” for their thesis, let me know.