Feldman and some of his colleagues have taken several trips to Australia in recent years, trying to figure out what that lesson might be. It's an increasingly popular destination, in fact, for Californians who are seeking answers to burning drought questions.
"Australia is seen as a model that has prevailed, and has created a kind of resiliency," Feldman says.
The Australian accomplishment that most impressed Feldman was the level of public awareness about the country's water situation, especially in cities like Melbourne.
"On the billboards, there were actually postings about the level of water remaining in the city's reservoirs," he says.
Australians now treasure their water in a way that most Californians still don't, Feldman says. In Melbourne, in recent years, the average person has been using just half as much water as the average person in L.A. You don't see nearly as many of those those green grassy lawns.
But a bigger challenge lies outside the cities. The biggest use of water by far, in both Australia and in California, is irrigation on farms. Agriculture is a huge industry in both places.
Some water experts say that the single most important thing that Australia did was to create a new way of allocating that irrigation water.
The old system in Australia looked a lot like the one that's still in place in California.
If you were a farmer, and owned irrigated fields, you had the right to use a certain amount of water either from wells or nearby rivers.
"It was seen as something that would just come to your property. It was joined to the land," says Tom Rooney, the founder of an Australian water trading company called WaterFind.
But in the years before the drought began, Australia carried out a giant reset of its water rights.
First, the government put a cap on the total amount of water available for farmers. Then, farmers received shares of that total supply. Each farmer got a share of the Australian water supply. It's similar to the way that stockholders own shares of a publicly traded company. And those water shares are not longer tied to any particular piece of land.
"Just like you have a title for your property, we have got a title for water," says Rooney. And just as people can buy and sell shares in a company, people in Australia can buy and sell shares of the nation's water supply.
So when the drought hit, reducing the total amount of water available, this market became a valuable way to distribute this scarce resource. Farms that were growing the most valuable crops were willing to pay more for water. They bought more shares. As the water price increased, other farmers found that selling their water shares was more profitable than growing a crop with it.
The end result: more efficient use of the country's water, and less economic pain.
Richard Howitt, an economist at the University of California, Davis, has been pushing for greater use of water markets in California. "The idea was very heretical a few years ago. I can remember being disinvited from meetings for saying it," he says.
Now, in part because of the Australian example, it's gaining ground, he says.
California probably won't adopt something as radical as Australia's national water market, Howitt says. But it already is getting more common for farmers to trade water in California. And he thinks people will be ready to adopt reforms that at least make it much easier to carry out such transactions.
Tom Rooney, apparently, things so. His company, WaterFind, which played a key role in creating water markets in Australia, now is setting up an American subsidiary based in Sacramento.