As California looks ahead to what could be a fifth consecutive year of drought, some of the Golden State’s residents remain thirstier than others. In the wealthy west Los Angeles neighbourhood of Bel Air, for example, one household reportedly used a staggering 11.8 million gallons of water last year.

That’s enough to fill approximately 1.5 Olympic-sized swimming pools every month, or to supply some 90 average homes. According to data uncovered by the Center for Investigative Reporting (CIR), the unnamed user glugged more water in the 12 months to April than anyone else in California. Under standard LA water rates, it would have cost them an estimated $90,000 (£60,000).

A leafy labyrinth of gated, palatial estates, Bel Air has counted among its residents Alfred Hitchcock, Michael Jackson, Jennifer Aniston and the Reagans. It is also home to four of the five thirstiest homes in California, records show. The other household in the top five is in neighbouring Beverly Hills – it used eight million gallons, making its owner just the third biggest water user in the state.

A small pool of water is surrounded by dried and cracked earth that was the bottom of the Almaden Reservoir in San Jose, California (Getty)

Indeed, all of the top 10 water users over the same period were from Bel Air, Beverly Hills or nearby Brentwood and Westwood. As many as 365 California homes each used one million or more gallons of water over those 12 months, according to the CIR statistics – and 92 of the top 100 were in LA.

Citing privacy concerns, the city of Los Angeles and other California water agencies declined to name the homeowners in question, let alone explain what they might have used all that water for. Fountains? Fish tanks? Golf course-sized front lawns?

Despite official targets designed to cut urban water use in California, few local water agencies have done anything to restrict the inordinate usage of individual residents, as long as they pay their bills and follow certain simple drought guidelines. And while the scale of such households’ consumption may be startling, the top 100 residential water users in LA account for just 0.2 per cent of the city’s total water usage.

Yet that has not prevented certain wealthy, well-known Angelenos from becoming the target of so-called “drought shaming”. Earlier this year, Magnum PI star Tom Selleck came to a $21,000 settlement with an LA county water district, after it emerged that someone had been improperly siphoning huge amounts of water from a hydrant in a different district, and using it to water Selleck’s 60-acre avocado ranch.

Kim Kardashian and Kanye West mansion in the Bel Air Crest neighborhood of Los Angeles, CA.

According to The Hollywood Reporter, the actor’s 26-year-old daughter, Hannah Selleck, a keen horsewoman, recently had to send her young horses to a ranch in New Mexico, where the green pastures they require to thrive are apparently untroubled by the drought.

When, in May, aerial images showed Barbra Streisand’s Malibu estate looking remarkably lush, representatives for the star – an avowed environmentalist – insisted she had already cut her water usage by 50 per cent, but would take further steps to make her extensive grounds more drought-friendly. Among the celebrities cited for water wastage recently were actor David Hasselhoff, musician and entrepreneur Dr Dre, and reality star Kylie Jenner.

During this summer, the fourth of the drought, the water content of the Sierra Nevada snowpack fell to a catastrophic 5 per cent of the average. Reservoir levels sank across the state as temperatures soared, with the state’s average annual temperature rising to about one degree warmer than the previous record, set in 1995-96. More than 813,000 acres of the state have been burned by wildfires during 2015.

Though the National Weather Service has put at 95 per cent the probability of an el Niño weather pattern causing major storms in southern California over the coming winter months, Californians have been warned not to rely on one season’s wet weather to reset the water table. In April, the state’s governor, Jerry Brown, ordered a mandatory 25 per cent cut in urban water use across California. Residents were urged to minimise their lawn-watering, car-washing and toilet flushing, and water agencies penalised hundreds who were caught wasting water.

So far, the state has managed to surpass that 25 per cent goal, though figures released last week suggested enthusiasm for water conservation is waning. In July, urban areas cut consumption by 31 per cent. In sweltering August, that number had dropped to 27 per cent, leading regulators to wonder if the number would continue to drop.