EPA broke federal laws when it used social media to promote its controversial Clean Water Rule, the Government Accountability Office concluded last month. That rule defines which waterways fall under the federal Clean Water Act, a pollution control and wetlands protection statute. The GAO investigation came at the request of Sen. James M. Inhofe (R-Okla.), who questioned EPA’s use of taxpayer dollars to raise awareness of the rule. Appropriations laws for fiscal 2014 and 2015 prohibit EPA from using its funds for unauthorized publicity, propaganda, or grassroots lobbying. During its investigation, GAO confirmed that EPA engaged in promotional campaigns on Twitter, Facebook, and Tumblr from February 2014 through July 2015 for the rule. The agency said it used social media campaigns with hashtags #DitchtheMyth and #CleanWaterRules to clear up misinformation surrounding the rule. Inhofe, chairman of the Senate Environment & Public Works Committee, is now raising questions about how the agency publicized its Clean Power Plan. That landmark air pollution rule, issued in 2015, will limit carbon dioxide emissions from fossil-fuel-fired electricity-generating plants.