APPLE VALLEY, Calif. — Outside her two-story tract home in this working-class town, Debbie Alberts, a part-time food service worker, has torn out most of the lawn. She has given up daily showers and cut her family’s water use nearly in half, to just 178 gallons per person each day.

A little more than 100 miles west, a resident of the fashionable Los Angeles hills has been labeled “the Wet Prince of Bel Air” after drinking up more than 30,000 gallons of water each day — the equivalent of 400 toilet flushes each hour with two showers running constantly, with enough water left over to keep the lawn perfectly green.

Only one of them has been fined for excessive water use: Ms. Alberts.

Four years into the worst drought in California’s recorded history, the contrast between the strict enforcement on Californians struggling to conserve and the unchecked profligacy in places like Bel Air has unleashed anger and indignation — among both the recipients of the fines, who feel helpless to avoid them, and other Californians who see the biggest water hogs getting off scot-free.

This wide disparity in enforcement is testimony to California’s vast and chaotic system for moving water from reservoirs and underground systems to homes. There are 411 separate water districts — some public, some private — and each of these local utilities has been charged with devising its own rules for saving water during the drought.