How to incentivize better groundwater use

by Ellen Bruno, Molly Bruce, and Katrina Jessoe

For more than a century, parts of California have been using groundwater faster than the resource can be replenished. As a result, aquifers are dwindling—a mounting challenge for irrigators, communities, and ecosystems. 

The negative impacts of over-extraction include subsidence, shallower wells running dry, and water-quality deterioration. If overextraction remains unaddressed, groundwater will become more expensive and less reliable. This could have rippling economic and social consequences. 

Strawberries, by Ellen Bruno.

California passed the Sustainable Groundwater Management Act (SGMA) in 2014 (ten years ago), a law that aims to protect and restore our aquifers. Going forward, traditional management tools may not be sufficient. To comply with SGMA’s mandates, new and creative management strategies are needed.  

Financial incentives can help change practices that contribute to groundwater overuse. Innovative programs already operate successfully in California’s Pajaro Valley, a prime farming region. Our research shows that these incentives have effectively influenced behavior and are less costly than other management options. 

The Pajaro Valley is an agricultural region between the Coastal Range and the Pacific Ocean, south of Santa Cruz and north of Monterey. It is well-known for growing crops like strawberries, apples, and artichokes—crops that, in addition to being lucrative, are also water-intensive. Agriculture accounts for 90% of the Pajaro Valley’s freshwater demand and contributes to the basin’s groundwater deficit of 12,000 acre-feet/year.

Pajaro Valley is similar to many of the state’s agricultural regions; current and projected water demand outpaces what existing resources can supply. 

Butter Lettuce, by Ellen Bruno.

But this region is taking a different approach to managing groundwater. In other parts of the state, individual pumpers generally don’t pay more for their water than the energy costs to operate groundwater pumps. Unpriced groundwater can lead to more pumping. The Pajaro Valley, however, charges groundwater users extraction fees. These fees incentivize irrigators to flexibly steward groundwater resources.  

Groundwater fees can be leveraged in two ways to improve sustainability: they can be increased to disincentivize pumping, which reduces overall groundwater use, or pumping fees can be offset using a rebate for recharge, which increases overall groundwater supplies. 

The Pajaro Valley began levying pumping fees in 1994 to generate revenue that helped fund basin management activities. For many years, the local water agency charged all pumpers the same price per acre foot for extracting groundwater. But in 2010, the agency started charging a different price for those inside a special coastal zone that receives recycled water.

This change provided an opportunity to understand how farmers respond to price increases. A comparison of groundwater use between those inside and outside the special zone, relative to their use before the price split, shows how an increase in water fees decreased groundwater use. Our study found that fees were effective at reducing water use, especially when farmers were given enough time to adjust. 

The local agency has continued to innovate with new incentive programs. One such program—called Recharge Net Metering, or ReNeM—provides rebates on pumping fees to landowners who improve infiltration on their property. Similar to solar net metering for electricity, ReNeM subsidizes groundwater recharge projects on private property. ReNeM’s subsidy is performance based, meaning the more water a project infiltrates, the bigger the rebate.

Our study results indicate that the ReNeM program is cost-effective. At roughly $570 per acre-foot of water, ReNeM increases water supplies at lower cost than other viable management actions. This calculation included the annualized capital costs of the design and construction of recharge projects, operation and maintenance and opportunity costs of land used for recharge instead of farming.

Financial incentives are not a perfect solution. They won’t work everywhere, but the success in the Pajaro Valley shows promise for other groundwater-dependent agricultural regions. Our research shows that financial tools can help achieve groundwater sustainability goals in a cost-effective way. 

Under California’s state groundwater law, local groundwater sustainability agencies are legally required to bring basins into balance by 2040. If these agencies want to succeed, they will need to innovate. The Pajaro Valley’s story offers hope. Learning from the region will be essential as California and the broader Western U.S. endeavor to more sustainably manage water resources in the years to come. 

Further readings

Bruno, Ellen M., Katrina Jessoe, and W. Michael Hanemann. “The Dynamic Impacts of Pricing Groundwater.” Journal of the Association of Environmental and Resource Economists, forthcoming. Draft available at: https://escholarship.org/uc/item/2mx8q1td

Bruce, M., Sherman, L., Bruno, E., Fisher, A. T., & Kiparsky, M. (2023). “Recharge net metering (ReNeM) is a novel, cost-effective management strategy to incentivize groundwater recharge.” Nature Water1(10), 855-863.  Available at: https://www.nature.com/articles/s44221-023-00141-1

More information on Recharge Net Metering can be found here: https://www.law.berkeley.edu/research/clee/research/wheeler/renem/

Ellen Bruno is an assistant professor of Cooperative Extension in the Department of Agricultural and Resource Economics at UC Berkeley. Molly Bruce is a research fellow at the Wheeler Water Institute at UC Berkeley’s Center for Law, Energy, and the Environment. Katrina Jessoe is an associate professor in the Department of Agricultural and Resource Economics at UC Davis.