Rainwater is no longer waste to be flushed into the ocean, but a strategic asset that reduces reliance on expensive imported water sources.
A rainy season that reverses LA's water equation
The 120.3 billion gallons of rainwater captured by Los Angeles County during the 2025-2026 storm season is more than just a weather record. It is more than ten times the amount captured the previous season (11.9 billion gallons, according to LA County Public Works), enough to supply water to 3 million people for a year — equivalent to the population of Chicago. Against the backdrop of Southern California having spent billions of dollars over the past two decades building rainwater capture infrastructure, this year's rainy season is the first large-scale test showing that the system works as designed — while also exposing limits that policymakers will have to face in the coming decade.
The problem is: a record rainy season does not solve Southern California's structural water problem. It merely buys time. And how the LA County administration, utilities, and residents — including more than 100,000 Vietnamese Americans living in San Gabriel Valley, nearby Westminster, and areas dependent on imported water — use that time will shape water prices, housing prices, and even the viability of traditional ethnic businesses in the community for years to come.
The nature of the numbers: groundwater, not reservoirs
It is important to clarify from the start: these 120.3 billion gallons are not water stored in open-air reservoirs like Diamond Valley Lake. Most of it is directed into what the water industry calls spreading grounds — large tracts of land along the San Gabriel and Rio Hondo rivers, where rainwater is deliberately retained to percolate down into the groundwater aquifer.
This mechanism is fundamentally different from surface water storage. Groundwater, once replenished, can remain in the soil for many years without evaporating — a decisive advantage in a climate where summer temperatures regularly exceed 38 degrees Celsius. According to data from the California Department of Water Resources, evaporation from open-air reservoirs in Southern California can reach 5-7 feet (1.5-2.1 meters) each year. The amount of water lost from large reservoirs like Castaic and Pyramid during a dry summer is significant.
Downtown LA recorded 16.9 inches of rain since October 2025, equivalent to 110 percent of the annual average — compared to just 6.6 inches the previous season, according to LA County Public Works data. Water captured at the county's reservoirs and spreading grounds reached 185 percent of the average for this time of year. This is the result of two factors: abundant natural rainfall, and significantly upgraded capture capacity thanks to the Safe Clean Water Program (Measure W) — a property tax measure approved by LA County voters in 2018 with a commitment to raise approximately 280 million dollars annually for rainwater infrastructure, according to the LA County Flood Control District.
Historical context: from a drainage system to a water capture system
To understand why the 120 billion gallon figure is a turning point, one must look back at LA's water infrastructure history. For nearly a century, from the catastrophic 1938 flood to the 2000s, LA County's rainwater infrastructure design philosophy was to push water out to the ocean as quickly as possible. The LA River, encased in concrete into a massive drainage channel — a familiar image in Hollywood movies — is the product of that philosophy.
As a result, for decades LA has discharged enormous amounts of rainwater into the Pacific Ocean while importing water from three distant sources: the Colorado River, the Sacramento-San Joaquin Delta in Northern California (via the State Water Project), and the Owens River basin east of the Sierra Nevada. According to the Metropolitan Water District of Southern California (MWD), approximately 50-60 percent of water supplied to the region comes from outside the watershed — a political-hydrological dependency where any drought in Northern California or legal disputes over the Colorado River can pose a threat.
The reversal began in the mid-2000s when scientists and local officials recognized that rainwater is not waste but an asset. Measure W in 2018 was the crucial turning point. This was followed by a series of specific projects: expansion of Tujunga Spreading Grounds, construction of the Sun Valley Watershed project, and dozens of mid-scale projects that transformed urban parks into rainwater capture sites.
Stakeholder analysis: winners, losers, and those to watch
Clear winners are groundwater management agencies — particularly the Water Replenishment District of Southern California (WRD), which manages the Central and West Coast Basin aquifers serving approximately 4 million people south of LA County. Every gallon recharged into the aquifer is a gallon they do not have to buy from MWD at rising prices — MWD's wholesale water rates have increased many times over the past decade, according to public reports from the agency itself.
Potential winners are small business owners dependent on water. Vietnamese nail salons — an industry where the Vietnamese American community holds significant market share in California — use water for disinfection, towel washing, and equipment sanitation. Pho restaurants and Vietnamese food processing facilities in San Gabriel Valley and Rosemead are all commercial water consumers. When local groundwater sources become more abundant, the pressure for price increases from MWD on retail distributors decreases — though nothing guarantees that utilities will pass these savings on to end consumers.
One to watch is Mark Pestrella, director of LA County Public Works, who has stated plainly that continuous maintenance, particularly sediment dredging, is vital to sustaining the system's capacity. This is not a vague warning. After each major flood, spreading grounds and reservoirs accumulate sediment — mud, sand, and debris from wildfires. Following the major fires in 2025 at Eaton and Palisades, the amount of sediment flowing into the water capture system is forecast to be substantial. Dredging is expensive — a major dredging project can cost tens of millions of dollars, and LA County faces budget pressure from post-fire recovery costs.
Potential losers are agricultural communities in the Central Valley and downstream Colorado River basin states if — and this is a big if — LA County actually reduces its dependence on imported water. But reality is more complex: even with record rainfall, LA will continue to import most of its water, since local capture infrastructure is still insufficient to replace imported sources in an average year, let alone during dry years.
Vietnamese American community perspective: hidden consequences
The Vietnamese American community in Southern California — concentrated in Westminster, Garden Grove, and Rosemead, but also dispersed throughout San Gabriel Valley, Long Beach, and El Monte — relates to the water story on multiple levels.
The first level is household economics. Water bills in cities like Westminster and Garden Grove (located in Orange County, not LA County, and therefore not directly benefiting from Measure W) have risen steadily in recent years due to imported water costs. For multi-generational Vietnamese households — a three-generation household model is quite common in the community — water costs for daily use and vegetable gardens (many Vietnamese families maintain herb gardens with water spinach, basil, Vietnamese coriander, and lemongrass) are a significant expense. Though LA County experiences abundant rainfall, Vietnamese residents in Orange County depend on the Orange County Water District and separate water sources — indirectly benefiting from reduced pressure on MWD but to different degrees.
The second level is ethnic economy. Nail salons, restaurants, laundromats — three industries where Vietnamese have significant presence — are all water-intensive businesses. A 2020 UCLA Luskin Center for Innovation study showed that small businesses owned by immigrants in Southern California are particularly sensitive to utility price fluctuations, given thin profit margins and limited ability to pass costs to customers. A record rainy season does not immediately change this, but if the trend of sustained groundwater recharge is maintained over many years, the pressure for price increases could slow.
The third level is local politics. In water board elections — races that typically have very low voter participation — Vietnamese American voters rarely participate at rates proportional to their population. Decisions about water rates, infrastructure investment, and groundwater recharge policy are usually made by boards where the Vietnamese community has little voice. The third Water Summit convened by Supervisor Lindsey Horvath in May is an opportunity for Vietnamese community organizations — such as VABA (Vietnamese American Bar Association) or community policy groups — to attend and represent the interests of small businesses.
International comparison: lessons from Singapore and Israel
To put LA's achievements in context, one can compare two world-renowned water management models.
Singapore, with its NEWater program and comprehensive rainwater capture system, now captures approximately 2/3 of the island's surface area as water catchment, according to Singapore's Public Utilities Board (PUB). The island nation has turned nearly every roof and every road into a water collection point. Israel, with desalination technology and agricultural wastewater reuse, has achieved approximately 90 percent wastewater reuse — the highest in the world according to many OECD reports.
LA County, despite its progress, remains in an early stage compared to these two models. The percentage of water being reused and captured locally remains below what is needed to achieve water independence — a goal officials like Horvath often mention. The gap between promise and reality is not small — and that is precisely the gap that the Water Summits will need to fill with specific financial and technical commitments, not vague statements about "resilience.
Outlook: three decisive questions
Looking ahead, three questions will determine whether the 2025-2026 rainy season is truly a turning point or merely a fortunate parenthesis in a long-term drought cycle.
First, maintenance budget. Pestrella warned about sediment dredging. The question is whether the LA County Board of Supervisors is willing to allocate maintenance budgets proportional to the new capture capacity. Unmaintained infrastructure loses capacity quickly — and the next large storm will witness lower capture rates despite the same rainfall.
Second, expanding Measure W. The current tax measure has specific spending structures through 2030. Whether it will be extended or expanded — and more importantly, whether it ensures priority projects for low-income communities, which bear disproportionate burdens from stormwater pollution — will be the major political battle in coming years.
Third, climate change. One large rainy season does not negate long-term trends. According to reports from UCLA and Scripps Institution of Oceanography, Southern California is shifting to a pattern of "extreme droughts alternating with extreme rainfall" — called climate whiplash. This pattern presents a dual challenge: infrastructure must be large enough to handle extreme storms, but also flexible enough to operate efficiently through long dry years.
Conclusion: impressive numbers, difficult work
120.3 billion gallons is a number to celebrate — and the LA County Board of Supervisors chose the right moment on Earth Day to announce it. But for a Vietnamese American community that has witnessed two major migrations (1975 and beyond), endured multiple harsh economic cycles, and operates small businesses dependent on stable utility costs, the real story does not lie in the number but in execution.
The record rainy season accomplished the easy part. The hard part — maintaining infrastructure, expanding capacity, ensuring equitable benefit distribution to immigrant and low-income communities — still lies ahead. The Water Summit in May 2026 will be the first test of whether officials can turn promises about resilience into specific budget commitments. And that is a meeting where the Vietnamese community — along with other immigrant communities struggling under rising utility costs — should not remain on the sidelines.