It’s A New Water Year. What Can We Expect Ahead?

October isn’t just the start of our spooky season — it’s also the official start of the new water year. Historically, our wet season has stretched from mid-October to April, and water managers across the state are gearing up for what could be an even wetter year than last year, given the El Niño climate pattern, and a changing water cycle driven by human-caused climate change.

So where do we stand when it comes to our water supply now? And how is L.A. preparing for potential flooding, as well as making sure all this needed water can be stored for dry years? We’ve got the rundown.

Where our water supply stands

After the driest three years in more than 100 years, 2023 surprised many water experts when Mother Nature took a dramatic turn and brought some of the most rain and snow we’ve seen in decades.

Scientists say those bigger extremes in “weather whiplash” are a clear sign of how our climate is changing.

That’s meant for now anyway, our water supplies are doing pretty well.

L.A. saw some 33 inches this last season — about double the amount we normally get.

That rainfall equated to about 600,000 acre-feet (the metric water is officially measured in). That translates to 193 billion gallons of stormwater captured in local groundwater basins to be used later, said Mark Pestrella, director of L.A. County Public Works, which is in charge of the county’s flood control and water capture system.

That’s enough water for 5 million people for a year, said Pestrella — more than enough water to serve the entire city of L.A.

“This would be considered our second-best year in stormwater capture,” Pestrella said.

The biggest stormwater capture year came in 2005, a fairly average El Niño year, when the county captured 700,000 acre-feet, he said.

In an average year, the county captures 250,000 to 300,000 acre feet of stormwater.

Super El Niño

Though forecasts are still uncertain, and we don’t yet know what local impacts may come, scientists at the National Oceanic and Atmospheric Administration, or NOAA, are predicting at least a “strong” and potentially a “super” El Nino this year.

While too much rain all at once poses significant challenges for our infrastructure — and is an increasing trend brought by human-caused climate change — water experts say we still need several more wet years to truly recharge groundwater basins across the state and locally.

“What we need is more rain like we had last year, where it comes in over time and not all at once — we really have no problem capturing water and protecting people from floods in those scenarios,” Pestrella said.

“We're actually in really good shape this year, but of course, we're also pulling water out and drinking it," he added. "It's really a matter of non-stop filling up the bank account.”

It’s also less clear how El Niño will impact snowpack in the Sierra Nevada, where much of L.A.’s water comes from. El Niño usually means it’s wetter here in the Southland, but it can also mean a drier year up north.

Why conservation still matters

Water conservation should still be a number one priority, said Pestrella, as well as Bruce Reznik, director of non-profit L.A. Waterkeeper, and Greg Pierce, the director of the Human Right to Water Solutions Lab at UCLA.

“We may be right back in the situation we were before this last wet year in a year or two, but it does appear that we're going to have another wet year, and that should set us up again to avoid desperation, for maybe, instead of one to two years, maybe three to five years,” Pierce said.

But that doesn’t mean conservation efforts should let up, given the fact human-caused climate change is driving a long-term drying trend across the West. That’s particularly impacting snowpack in the Sierra Nevada and the Colorado River — still the primary sources of the Southland’s water supply.

“It is crucial that we adopt the strongest possible conservation regulations,” Reznik said. “It always has to be the biggest priority for our long term future.”

The State Water Resources Control Board is considering a regulation to permanently ban using drinkable water to irrigate purely decorative grass.

Outdoor watering accounts for roughly half of Southern California’s water use and the Metropolitan Water District, which provides water to 19 million people across the Southland, said such a regulation could reduce the region’s total water use by nearly 10%.

And recently the city of L.A. announced $19 million in state funding to boost water conservation efforts, including about $14.6 million that will fund replacing lawns with native plants or otherwise water-efficient landscapes for free to Los Angeles Department of Water and Power (LADWP) customers in single-family homes in low-income and pollution-burdened communities. The program is set to launch in 2024.

Challenges to come

Some of the main challenges to L.A. and much of the Southland’s water supply are:

• The need to clean up heavily contaminated groundwater basins to make room for more local water storage.
• The need to clear sediment that’s accumulated in reservoirs and debris basins to store more local water and shore up flood control.
• The need to make decisions about long-term major investments in water recycling and ocean desalination.

Go deeper

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From Drought to Deluge: The Story of the Biggest, Wettest Winter in Western History

The Push To Reimagine LA's Streets And Alleyways To Fight Both Drought And Floods

Local Water Projects Get Funding Boost From State To Ease Growing Flood Risks