Waters of the U.S. Action Center


WOTUS is a term used in the Clean Water Act 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 December 11, 2018, the Trump Administration released a new proposed WOTUS rule. NACo is currently analyzing this proposed rule.

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.


  • Associate Legislative Director – Environment, Energy & Land Use  
    (202) 942-4269

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