Groundwater is instrumental in slaking California's thirst. In average years, underground basins, known as aquifers, supply about 35% of the water used by the state's cities and farms, and in drought years, that figure can jump to 60% or higher.
Many areas of the state rely exclusively on groundwater for their supplies, while other areas use groundwater to supplement their surface supplies or to meet needs when surface water is not available.
As surface water deliveries continue to be constrained, California is relying more and more on groundwater to meet needs. The shift to greater reliance makes effective management a critical challenge as the state works to implement the Sustainable Groundwater Management Act of 2014 (SGMA).
The SGMA is a comprehensive three-bill package that provides a framework for sustainable management of groundwater supplies by local authorities, with a limited role for state intervention only if necessary to protect the resource.
The SGMA is considered just one part of a statewide, comprehensive water plan for California that includes investments in water conservation, water recycling, expanded water storage, safe drinking water, wetlands and watershed restoration. The plan is intended to ensure a reliable water supply for California for years to come.
Ultimately, for sustainable groundwater management to succeed, California must also invest in conveyance improvements in the Delta, additional surface storage and groundwater storage to optimize both water supply reliability and ecosystem health, and substantial investments in local water resources development.
For more information on SGMA, please visit ACWA's groundwater spotlight page .