Underneath pavement, parks and lawns, a web of pipes carry the water that fuels urban life from the companies that distribute it to the people who consume it. Many Americans never think twice about how much water might be leaking from that system.  And water providers haven’t always been required to contain the leaks. 

In California, though, that’s changing. The state, notorious for its battles over scarce water, is developing regulations that would require large urban water providers to analyze, then reduce the water they lose to leaks or metering errors before a single drop reaches consumers. California would be the first in the nation to set state-mandated loss standards, although it’s already two years behind its deadline to do so. 

Regulators say they expect to adopt the rules before the year ends, tying up a process that’s been mired in disagreement and delays. Meanwhile, the state has asked residents to curtail their own consumption to cope with a punishing drought.

Reducing system losses won’t be a cure-all; research suggests the Southwest is amid its driest period in 1,200 years and much of California’s water goes to other uses, like agriculture and protecting rivers, while about half of urban use goes to landscaping. But the standards could act as a common-sense measure to help tighten California’s water budget, as climate change continues to challenge water supplies.  

“Whether it’s this drought, or the next drought, or the next drought, the state of California will always have water supply challenges,” said Sue Mosburg, the executive director of the California-Nevada Section of the American Water Works Association, a drinking water industry trade group. “Water loss should be one of the many water efficiency areas that everybody considers.”

California’s urban water suppliers lose about 300,000 acre feet of water per year, according to estimates from the State Water Resources Control Board, which regulates water quality and rights. That’s roughly enough to fill 156 Olympic-sized swimming pools—a “good chunk of water,” said James Nachbaur, the board’s director of research, planning and performance. U.S. water utilities on the whole lose about 17 percent of the water they provide each year, according to researchers, either through actual leaks or metering errors and theft, called “apparent losses.”

Historically, water utilities haven’t often had to consider leaks or diminishing water supplies, according to Ellen Bruno, an assistant professor of cooperative extension in the department of agricultural and resource economics at University of California, Berkeley. But water shortages, expected to become more frequent due to climate change, are changing that. 

“It’s only when, as time has gone on and supply augmentation isn’t a feasible strategy for getting enough supply to meet demand, that utilities have started to think about other strategies to encourage household conservation and [started] moving in this direction of water conservation,” said Bruno.

California is among only a handful of states that currently require water providers to monitor the amount of water they lose due to leaks. An analysis conducted by Bruno and colleagues at the University of California, Davis, and published in February looked at data from the four states that make data on water supplier leaks available: California, Texas, Tennessee and Georgia (Georgia also requires water suppliers to establish goals for water efficiency and demonstrate progress towards achieving them). The researchers found that the median utility could economically reduce leaks by nearly 35 percent.

Bruno and her collaborators found that California’s water losses are already relatively small compared to the other states in that group. Their analysis suggests California would see water savings of just 1.8 percent if it instituted the most cost-efficient standards. But Bruno says such standards are still worth pursuing because they’re often the least-cost option for water utilities to augment supplies, cheaper than other water-scrimping measures like desalination and recycling, both of which California plans to invest heavily in.

“Relative to other measures for water savings, leak reduction is low hanging fruit,” she said.

California, ever on the search for more water, is also in its third year of drought. The state believes the average water connection in California loses about 35 gallons per day.

“If that was happening inside your house you would be all over it. You’d be fixing that very quickly. But because the leaks are happening underground, out of sight, they don’t get as much attention,” said Nachbaur.

Despite general consensus about the utility of the rule, the standard itself has been a controversial one. And its development has been delayed.

California’s then-Gov. Jerry Brown signed Senate Bill 555 in October 2015, years into the state’s last severe drought and a few months after he  placed the first-ever mandatory restrictions on statewide water use, which required cities and towns to reduce water usage by 25 percent. The new law required urban water suppliers to start submitting annual, validated audits documenting water losses. By July 2020, it also required the state to establish performance standards for the volume of losses it would allow. But the water board didn’t start official rulemaking on those standards until December 2021 and was still tweaking the text of the regulations into September. 

Max Gomberg, who helped shape the standards as the water board’s conservation and climate change manager, said the pandemic, a gubernatorial transition, and personnel change at the water board delayed the rule. But he also pointed to pressure from water systems who wanted to change the standard and low prioritization of the rule as clogs in the process. Gomberg resigned from the water board in July, expressing frustrations with the agency’s inability to create regulations that would lead to the type of transformational change he sees as necessary to confront climate change.  

Much of the acrimony around the water loss rule has revolved around the complex and, according to Mosburg, “highly contentious” model that determines how much each water system must reduce losses. Rather than establish a single standard, as some countries have done, California created an equation designed to  balance cost with benefits for each of its more than 400 large water suppliers. The water system serving the city of Atwater in California’s Central Valley, for instance, may have to cut losses by 95 percent, according to data from the state, while others, like the water system in the City of Cupertino, in Silicon Valley, won’t have to make any reductions.

A “drumbeat of utility criticism” surrounded the refining of that model, said Ed Osann, director of national water use efficiency at the Natural Resources Defense Council. He said California’s tailored approach was an ambitious one, and the complexity of developing the model tacked time onto the process. Some water suppliers and industry groups are still not satisfied with it, though Gomberg thinks they’ve often been able to sway the board.

“They have been very successful at preventing the state from imposing what I consider to be the kinds of regulations and the kind of enforcement regime that are sorely needed to reduce the harms that we are experiencing and are accelerating due to the way climate change is impacting the state’s hydrology,” said Gomberg.

The water board disagreed with that position and, in an email, a spokesperson pointed to “unprecedented, real-time regulatory actions” that the agency had undertaken in the last year in response to the drought.

During development of the standard, some water agencies expressed concerns that costs would outweigh the benefits of water savings; the state requires that cost and benefits be equal. The analysis from Bruno and her team suggested going further—maximizing benefits relative to cost.

Joe Berg, water use efficiency director at the Municipal Water District of Orange County, has participated in the standard development process for years. His agency serves more than 3 million California residents through 27 water agencies. Berg doesn’t want agencies with already-low losses to be required to do certain state-mandated surveys, and Berg has raised other concerns with the model.   

Questions also remain about the accuracy and scope of the data the state is using to build the standard; the state itself recognizes it has been a challenge to get the data it needs. Water suppliers are relatively new to auditing and reporting their losses.

Amy Talbot, regional water efficiency program manager at the Regional Water Authority, a joint powers authority representing water providers in Northern California, also thinks the model will need tweaks, but she’s ready to move out of rulemaking limbo.

“No model is perfect,” she said. “At some point, you have to just move forward with what you have and then revise as needed.”

California’s constitution requires the state to reduce any waste of water. Last summer, California Gov. Gavin Newsom asked residents to voluntarily cut use by 15 percent — a target residents have not met. The state is also at work on efficiency standards for residential indoor and outdoor water use and for commercial irrigation. But the water loss standards, if approved, would be the only rules to regulate not what customers use, but what suppliers lose.

The state won’t be able to entirely zero out those losses, but California could make an invisible issue more visible, and possibly encourage more states to do the same. When the standards are adopted, water providers have until January 2028 to implement them, unless they’re allowed more time from the board. Confronting leaks will be a yearslong process.  

“It’s like a tax on all of the water system,” said Osann. “That’s why it’s important to be working on it in wet years as well as dry years.”