There is no comprehensive regulation of groundwater use in the state of California,* and the right to withdraw groundwater is based on surface land ownership. This creates a direct linkage between every land use that requires water and the groundwater underneath that land. Because so many aspects of groundwater use are not regulated by the state, local governments’ land use decisions become a key driver of demands on groundwater. Nonetheless, land use decisions and planning are not well coordinated with groundwater management.

Understanding how land use decisions affect groundwater resources has become increasingly important in recent years, as groundwater provides approximately 30 percent of California’s water supply in average years and 40 percent of the supply in dry years. In some places, the reliance on groundwater during droughts is much higher, due to reduced supplies of surface water. Growth from housing and irrigated agriculture, among other demands, have led to chronic overdraft and declining groundwater elevations in many communities that rely heavily on groundwater.

To address this problem, Water in the West convened groundwater managers, land use planners, water lawyers, consultants and academics at Stanford University for an Uncommon Dialogue in the fall of 2013. Its aim was to discuss a growing consensus that more effective integration of land use planning and groundwater management is an essential component of preserving groundwater aquifers for the future, and to share possible means of accomplishing this in California.

This report, shaped in part by the Dialogue, provides the background and regulatory context for land use planning and groundwater management in California, shares case studies that highlight the intersection of groundwater and land use, and makes specific recommendations to improve the linkage between land use decisions and groundwater management in the state.

*The Sustainable Groundwater Management Act (SGMA) was signed into law five months after this was published.