By the time a drop of California-treated water reaches a consumer’s tap, approximately 8% of it has already been wasted due to leaks in the distribution system. Nationally, waste is even higher, at 17%. This represents an untapped opportunity for water savings, according to a study from the University of California, Davis.
The study, published in the journal Environmental Research Letters, is the first large-scale assessment of utility-level water loss in the United States. He found that utility leakage reduction can be the most cost-effective tool in an urban water manager’s toolbox, provided that utility-specific approaches are used.
“When I first heard of ‘leaks’ I thought it sounded boring, but leaks are a huge component of our water systems and have greater opportunity than many other methods of saving water to have an impact,” said lead author Amanda Rupiper, a postdoctoral fellow at the UC Davis Center for Water-Energy Efficiency. “As the first state to regulate its water losses, many eyes are on California, and this is an opportunity to impact policy here and abroad.”
Amid a years-long drought, the passage of Senate Bill 555 in 2015 made California the first country in the nation and one of the first in the world to require water utilities to regulate their water losses.
Using data from more than 800 utilities in California, Georgia, Tennessee and Texas, the authors characterized water losses across the country. They developed a model to assess the economically efficient level of losses and used this model to compare various water loss regulations and modeling approaches.
The study found that one-size-fits-all approaches to leak management are not efficient, economical or equitable for utilities, which vary in size and resources. One-size-fits-all approaches could lead to poor management of urban water losses. However, applying utility-specific performance standards can generate a similar amount of water savings to the benefit of both the utility and society.
“Regulations that impose a uniform standard on all utilities will result in water reductions that are too stringent in some cases, too lax in others, and too costly overall,” the document concludes.
Save drips without draining utilities
Ideally, no leaks would occur in a system. However, while some leaks are obvious and accessible, others may be harder and more expensive for some utilities to find and repair. The authors’ model assessed when utilities could save the most water for their money in order to find and fix leaks in the system.
They found that for the median utility, it is economically efficient to reduce water loss by 34.7%, or 100 acre-feet per year. The median cost of water savings through leak management is $277 per acre-foot – cheaper than most traditional water management tools, including conservation campaigns and rebate programs.
“It’s cost competitive and it should be part of the profile of how we manage our water,” Rupiper said. “We tend to think of leaks as a small drip, but leaks are not inconsequential. Drops add up to big flows, and we can’t ignore them anymore.”
The study’s co-authors are Frank Loge, Joakim Weill, and Katrina Jessoe of UC Davis, and Ellen Bruno of UC Berkeley.