The number of CAFOs has grown rapidly. There were 146 CAFOs in 2005, and 264 in 2014.

DNR record-keeping had become so spotty it was impossible to tell how often pollution violations led to enforcement action. The department had lower than a 50 percent success rate at meeting its goal of inspecting each CAFO twice every five years. Under the law, CAFO operators dispose of thousands of tons of manure on fields and are expected to tell the DNR if they do it in ways that threaten water.

In response to the audit, the DNR said it needed to add enough field staff so that each employee had responsibility for no more than 20 CAFOs. Two years ago, Walker and the Legislature approved a plan to shift four DNR workers from other areas into the CAFO department.

That increased the number of front-line field workers to 14. The DNR has also added coordinators who work to make enforcement consistent statewide, and specialists who make field staff more efficient by handling water protection evaluations of CAFO plans for disposing of manure on farm fields, said Brian Weigel, deputy director in the DNR watershed bureau’s runoff management program.