How UC Berkeley mapped groundwater inequality across California’s Central Valley using Regrid's nationwide parcel data

Industry

Education

Challenge

UC Berkeley researchers needed a practical way to identify who owned which wells and link groundwater access to cropland ownership.

Results

Using Regrid parcel data, the team matched 12,000 wells to 10,000+ cropland parcels and produced a first-of-its-kind, owner-level snapshot showing the top 10% of well owners control 46% of groundwater capacity.

Key Product

Enterprise Data

www.berkeley.edu

"This project really came about because one of our colleagues discovered the Regrid data and encouraged us to look into it. Once we saw what was possible, everything followed from there."

Benji Reade Malagueño

Researcher, University of Berkeley

ABOUT

The University of California, Berkeley’s Department of Environmental Science, Policy, and Management (ESPM) conducts interdisciplinary research on how human and natural systems interact, with the goal of informing sustainable policy and environmental governance. In this project, the team focused on land and water ownership patterns in California’s Central Valley and their implications for groundwater equity.

THE CHALLENGE

Understanding who controls California’s groundwater has long been constrained by messy, incomplete data. Public well databases often lack owner names and map wells with only approximate coordinates, sometimes placing them at the centroid of a one-mile PLSS section rather than the true location.

At the same time, parcel and owner information exists in county assessor records, but those records are fragmented across 19 counties with different schemas, formatting, and update cycles—making manual aggregation slow, inconsistent, and difficult to standardize. Without consistent parcel geometry, ownership attributes, and unique identifiers like APNs, the team couldn’t reliably link wells to farms or analyze inequality in groundwater access alongside cropland ownership.

THE SOLUTION

Through Regrid’s Data With Purpose (DWP) program, the UC Berkeley team gained access to a standardized, multi-county parcel dataset that became the foundation of the analysis. Delivered as a bulk dataset via SFTP and processed in RStudio, Regrid’s consistent parcel geometry and ownership attributes made multi-county work feasible at an academic budget.

The researchers used Regrid fields—especially APNs (the key unique identifier), along with owner names and addresses—to match 12,000 groundwater wells to 10,000+ cropland parcels across the Central Valley. They combined attribute-based matching with selective spatial joins to handle cases where well coordinates were less precise.

"We wouldn’t have been able to know who owns which wells or where they were located without the Regrid data."

— Benji Reade Malagueño

THE RESULTS

With Regrid parcel data as the backbone, the team produced the first quantitative, owner-level snapshot of land and groundwater inequality across California’s Central Valley, matching 22k assets in total (10k parcels + 12k wells).

Key findings showed how concentrated control has become: the top 10% of well owners control 46% of groundwater capacity, and land ownership is even more unequal—raising new questions about how property systems and water governance interact under SGMA.