As implementation of the 2014 Sustainable Groundwater Management Act (SGMA) proceeds, it’s no secret that the San Joaquin Valley will have to adapt to a future with less water for irrigation. Our research shows that overall irrigation supplies may decline by as much as 20% by 2040. Land uses will have to change, and some have raised concerns that SGMA’s implementation could put smaller farms at a disadvantage, given their more limited resources and capacity. To gain insight on these issues, we conducted a detailed geographical analysis of cropping patterns and water conditions by farm size on the San Joaquin Valley floor, using county real estate records on ownership of agricultural parcels (individual properties of varying sizes) to identify farms.