California's State Water Resources Control Board has adopted a Dairy Remand Order that directs the Central Valley Regional Water Quality Control Board to rewrite its general order for dairies, with new requirements on manure lagoons, nitrogen use and groundwater, California Ag Network reports.

The order ends a process that began when the regional board adopted its current dairy order in 2013 and it was immediately challenged. The state board took up the petition in 2018, published a first draft in October 2024 and a second in June this year, released the proposed final on 4 September and adopted it on 15 September. It applies only to Central Valley dairies, and it does not bind dairies directly: it tells the regional board how to revise its own order.

By September 2027 the regional board must build a risk-based framework and start writing to dairies in areas of shallow groundwater. Each must either show that its lagoon does not intersect groundwater or rebuild it; the final text lets the regional board move at a pace that matches its resources.

Within two years dairies must measure the nitrogen they apply to cropland more accurately, for example with flowmeters. The state board will also set new groundwater loading limits for dairies and, for cropland, a multi-year land application rate formula, both to be written into the regional board's final order.

The rules bite hardest on growth. A dairy that expands between 15 September 2026 and the regional board's final order must meet a nitrogen land application ratio of 1.4 for the added part of its herd at once. One that expands after the final order must meet every final standard before it grows, with no time schedule, while existing dairies and those in the first expansion window have up to 35 years to comply.

California Ag Network notes that the practices and technology needed to meet the final standards are likely not readily available to dairies today.

Photo: USDA Natural Resources Conservation Service / Wikimedia Commons (public domain)

Source: California Ag Network