Hotter, drier weather could nearly double household water bills in some American cities by midcentury, according to a Stanford-led study published July 8 in Nature Sustainability. The research, led by Jennifer Skerker, a doctoral student in civil and environmental engineering, is the first to model how climate change, the cost of new infrastructure and household demand combine to push an already growing affordability problem toward a breaking point.

The team built its model around Santa Cruz, California, a small coastal city that draws almost entirely on local surface water and a single reservoir with barely a year of storage. That makes it unusually exposed to drought and a useful test case, the authors said, because the city has already used up cheaper conservation options such as restricting irrigation and switching to water-efficient appliances.

The numbers are stark. Under a dry-climate scenario, median monthly water bills for the poorest residents could rise from about $60 to $111 in today’s dollars. Paying for the needed infrastructure could push the share of local households above the U.S. Environmental Protection Agency (EPA) affordability threshold from 19% to 35%. More than 5% of households could end up spending as much as a third of their income on water, forcing hard trade-offs against food, health care and other basics.

“Climate change stresses water supplies and forces utilities to build expensive new infrastructure to maintain reliability,” Skerker said. That construction — desalination plants, water-reuse systems, new pipelines — is costly, and utilities pass the expense on to ratepayers.

How a city pays for resilience matters as much as the climate itself. The study found that a build-early approach adding large desalination capacity delivered reliable supply but at a steep cost to affordability, while a wait-and-see approach kept bills lower but provided reliable water in only six of ten years on average.

“Under today’s financing and regulatory models, climate adaptation and water affordability are on a collision course,” said senior author Sarah Fletcher, an assistant professor at the Stanford Woods Institute for the Environment.

The warning sits atop a longer trend. The average cost of tap water in the United States has risen three times faster than inflation over the past two decades, driven largely by aging pipes and deferred maintenance. Water has long been one of the cheapest lines on a household budget, in part because most communities draw from nearby sources and are shielded from the global forces that move gas and food prices.

That is changing. When Hurricane Helene tore through western North Carolina in 2024, it caused nearly $3.7 billion in damage to the region’s water systems, and in Asheville it took 53 days to restore drinkable tap water to the whole city. In Corpus Christi, Texas, four years of drought pushed the city to approve nearly half a billion dollars for new water sources, and the city manager has said residents will likely see rates double over the next few years.

The researchers said the framework can be applied to other exposed cities, naming Los Angeles, San Diego, San Francisco, and abroad Cape Town and Melbourne. Even places that look secure could grow vulnerable as utilities raise rates.

The finding fits a wider pattern. A separate analysis from MIT Sloan economists Christopher Knittel and Catherine Wolfram, with UCLA’s Kimberly Clausing, estimated that climate change is already adding hundreds of dollars a year to household budgets — more than $1,000 in some regions — through insurance premiums, utility bills and disaster losses, including an average $360 increase in home insurance premiums between 1990 and 2023.

For families, the throughline is simple. The cost of a warming climate is not only wildfires and floods on the news; it turns up on the monthly water, power and insurance bills households pay whether or not they follow the science.

JBizNews Desk | Stanford, California

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