Rising temperatures and dwindling rainfall could push water bills sharply higher for residents of drought‑sensitive communities, a new study led by Stanford University warns.
Modeling future water costs in Santa Cruz
Researchers examined Santa Cruz, California, a small coastal city that relies almost entirely on local surface water and a single reservoir. Over the past twenty years, the city cut water use by nearly two‑thirds through conservation measures, including water‑saving appliances and reduced irrigation.
Using data from the local water department, lead author Jennifer Skerker, a PhD candidate in civil and environmental engineering, and her team built a computer model that combined projected temperature and rainfall changes with utility decisions such as building a wastewater‑reuse plant, setting rates, and forecasting household demand.
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The model tested two contrasting strategies. One called for constructing a major desalination facility to treat seawater or brackish groundwater, a move that would secure supply but raise costs dramatically. The alternative delayed large‑scale investments, keeping rates lower in the short term but leaving the system vulnerable; under that plan, reliable water would be available in only six out of ten years on average.
Financial projections were stark. In the desalination scenario, the median water bill for Santa Cruz households could double by mid‑century. Under a dry‑climate outlook, the share of families exceeding the EPA’s affordability threshold would rise from 19 percent to 35 percent, with the poorest seeing monthly costs climb from about $60 to $111 in today’s dollars.
Broader implications for water‑scarce cities
The research notes that the modeling framework can be adapted for other municipalities confronting similar pressures, including Los Angeles, San Diego, San Francisco, Cape Town and Melbourne. Larger reservoirs or interconnected water networks may mitigate some costs, yet the core dilemma—balancing reliability with affordability—remains.
Nationally, the average cost of tap water has risen three times faster than inflation over the last two decades, a trend attributed to aging infrastructure and deferred maintenance. The authors suggest that climate‑driven upgrades could exacerbate this trajectory, especially for low‑income households that already allocate a larger portion of income to utilities.
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“Climate change stresses water supplies, and forces utilities to build expensive new infrastructure to maintain reliability,” Skerker said in a release. “In cities already struggling with affordability due to aging infrastructure, the additional costs passed on to ratepayers to pay for additional infrastructure and reliability measures can push a substantial share of households into crisis.”
As municipalities grapple with the need to “drought‑proof” their water systems, the question of who pays for the upgrades looms large.
Many households could see a significant portion of their income devoted to a basic necessity.
