Waters of the U.S. Action Center


WOTUS is a term used in the Clean Water Act (CWA) to determine which waters and their conveyances fall under federal and state permitting authority. In 2015, the Obama Administration finalized a new and controversial WOTUS definition which was immediately challenged in the courts. Currently, the pre-2015 WOTUS rule is in effect in 28 states and the 2015 WOTUS rule is the law of the land in 22 states.

On February 14, the U.S. Environmental and Protection Agency (EPA) and the U.S. Army Corps of Engineers (Army Corps) officially released the Trump Administration’s proposed new WOTUS rule defining which bodies of water are subject to federal regulations under the CWA. This action represents the second step in the process taken by the EPA and Army Corps to review and replace the Obama Administration’s 2015 WOTUS rule.

In response to the proposed definition, NACo submitted two sets of comment letters. The first letter, with the National League of Cities and the U.S. Conference of Mayors, highlighted the opportunities and challenges that counties, cities and mayors potentially face. The second letter, is county exclusive and went into more details on how the rule could potentially impact counties and offered recommendations. For more information, click here.

County owned infrastructure potentially impacted by WOTUS designations

  • ​​​​​​Public Safety Water Conveyances: Roads and roadside ditches, flood control channels, drainage conveyances, culverts, etc.
  • Stormwater Municipal Separate Storm Sewer Systems (MS4): Comprised of channels, ditches and pipes
  • Green Infrastructure Construction and Maintenance Projects: Includes, but not limited to low-impact development projects (LID), bioswales, vegetative buffers, constructed wetlands, stormwater detention ponds, etc.
  • Drinking Water Facilities and Infrastructure Reservoirs, dams, ponds, canals, large water transport systems (Central Arizona Project, California Aqueduct, Colorado River Aqueduct, etc.)
  • Water Reuse and Infrastructure: Includes facilities built to generate additional water supply, their ponds, recharge basins, canals and ditches.