How Los Angeles learned from its megadroughts to save more water. It needs to conserve a lot more

NZ Herald

30-06-2025

In 1990, when its population was 3.4 million people, LA's annual consumption was 680,000 acre-feet of water, according to the city's water authority. (The industry metric, an acre-foot, is about half an Olympic swimming pool.)
With a population of 3.9 million, the city today consumes 454,000 acre-feet per year.
So how did this happen?
The shift has involved some simple, practical, boring fixes, like better plumbing, alongside larger transformations in social norms, policies and politics. Call it generational evolution, a slow but inexorable force.
With Los Angeles, it began after a series of dry spells.
A couple of megadroughts — one during the mid-1970s, another that lasted from 1987 to 1992 — shook California.
'Conservation' became part of the popular lexicon. State legislators passed laws commanding agencies and municipalities to save more water.
Politicians, public service announcements and schoolteachers all urged Californians to water their lawns less and to take shorter showers.
In time, Los Angeles became more than just mindful. It became an unlikely paragon of urban water conservation.
Its shift still hasn't solved the city's water problems, obviously.
A recent report commissioned by Governor Gavin Newsom estimates that, with more severe droughts predicted, the state could lose up to 10% of its water supply by 2040.
California's farms, many of them in the state's Central Valley, help feed the US by growing food for livestock, like alfalfa, and other crops, like almonds.
These thirsty plants gulp four times more water than all of the state's cities combined.
The region is at a critical juncture.
Conservation has been a huge step, but more practical fixes and gradual cultural shifts may not be enough to bring about water security.
There are basically two paths forward. One would draw yet more water to the south from Northern California, while the other would build on conservation efforts and create even greater self-reliance in the region. Both would require large-scale infrastructure that is very, very expensive.
Los Angeles now relies for three-quarters of its water on far-flung sources like the Owens and Colorado rivers, which are drying up, and an even more distant tributary of the Sacramento River in Northern California.
For generations, Californians have been debating a megaproject called the Delta Conveyance to hasten supplies south from the Sacramento-San Joaquin Delta.
That project, which would shore up infrastructure that is ageing and vulnerable, is opposed by many residents in the delta and by some farmers, and it won't specifically help Los Angeles. Recent cost estimates top US$20 billion.
More desalination plants (there's one in San Diego County) could tap into the Pacific Ocean. The latest plants have become less abusive to sea life and coasts, but they're energy-intensive and much costlier for consumers than existing water supplies.
The second option is for Los Angeles to recycle more water. Environmentalists all agree it's the best choice.
But recycling facilities could end up costing taxpayers as much as the Delta Conveyance, if not more.
Building Toward a Better Future
In 1913, a self-taught engineer named William Mulholland oversaw the completion of the Los Angeles Aqueduct and transformed the concept of a modern city.
Before then, Angelenos banked on the Los Angeles River, a fugitive watercourse prone to catastrophic floods, thwarting downtown development.
City authorities decided to send Mulholland north to devise a route by which a river that snaked through the Owens Valley could be diverted to Los Angeles.
The city acquired properties from unsuspecting farmers in the valley. Mulholland hired labourers to dig tunnels and erect hydroelectric plants powered by the water that gravity pushed through the aqueduct.
The city expanded so rapidly that it almost immediately had to look for more water.
Over the following decades, Angelenos extended Mulholland's aqueduct northward and southeast, hoarding water from the Colorado River. Eventually, the city began to import from the State Water Project, which taps into the Sacramento-San Joaquin River Delta.
For decades, the Los Angeles aqueduct allowed millions of Angelenos with green lawns to weather droughts and live another smoggy day in paradise without having to think too hard about where their water came from — or whether it might someday run out.
Until nature started declining to be conquered.
Angelenos had to start thinking harder, spark a coming together of politics, ingenuity and resources around a still young century's growing water problem.
Something like this happened after the megadroughts during the 1970s and into the early 1990s moved millions of Californians to reconsider their relationship to the environment.
In Los Angeles, a culture of conservation was promoted by fledgling environmentalists and community groups, and city authorities began to restore urban wetlands that had suffered from decades of abuse and neglect.
Machado Lake, for example, in the shadow of an oil refinery, had become a toxic cesspool. It was given a costly makeover, completed in 2017, that produced a leafy park.
'Places like Machado,' said Mark Gold, the director of water scarcity solutions for the Natural Resources Defence Council who served on the California Coastal Commission, 'helped convince residents that water matters'.
'It didn't increase the drinking water supply. But for Angelenos to care about conservation, they first needed to think of water as not just something that somehow gets piped from wherever into their faucets and shower heads. They needed to see it as a part of what they love and want to preserve about the city.'
More prosaically, public officials enticed residents to save water by offering rebates to homeowners who replaced lawns with more drought-tolerant plants.
The City of Los Angeles has so far swapped out some 53 million square feet (5 million sqm) of lawn, exceeding goals set by Governor Jerry Brown for the entire state in 2015.
By 2018, this ethos of conservation had come to be so thoroughly ingrained that a two-thirds majority of voters in Los Angeles County approved a measure to, in essence, tax themselves if they owned properties with impermeable driveways or other hard surfaces that prevent rain from replenishing groundwater basins. Measure W, as it's called, raises some US$280 million a year.
But to be truly self-reliant, the city will still probably need to construct recycling plants, two of which are on the drawing boards.
The Metropolitan Water District of Southern California, the government agency that delivers much of the region's water via the Colorado River and the Sacramento-San Joaquin Delta, is hoping to complete one of them; the City of Los Angeles is planning another.
The current goal for Los Angeles County is that by 2045, 80% of its water will come from recycling, increased stormwater capture, and conservation.
Studies suggest that if Angelenos just stopped watering their lawns, reducing per-person consumption to the same amount of water that Western Europeans average, the city would solve many of its water problems. Nearly half of residential water use in greater Los Angeles goes to outdoor landscaping.
'We are going to have less water by 2040; that's the reality,' Gold said. 'We've made gains with conservation. But the clock is ticking.'
This article originally appeared in The New York Times.
Written by: Michael Kimmelman
Photographs by: Adali Schell
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