No one told Jack LaPant that he could be in violation of the Clean Water Act for farming his own land. That’s mostly because the federal law includes a clear exemption for “normal” farming activities. But it’s also because the government officials LaPant consulted didn’t view overturned dirt that has been tilled and plowed as pollution. In 2016, the Army Corps of Engineers, which administers the Clean Water Act with the Environmental Protection Agency, began legal action against LaPant for plowing he did in 2011 to plant wheat on a ranch property he owned in Northern California. But in March...