As part of the rollback of environmental regulations, the Trump Administration has finally completed their longed for repeal of the 2015 definition of Waters of the United States (WOTUS). The EPA and Army Corps under Trump have targeted this rule as one of their priorities in regulatory reform. The agencies provided four reasons for the repeal: 1) the rule did not implement the legal limits on the scope of the agencies’ authority under the Clean Water Act (CWA) and Supreme Court precedent; 2) the rule failed to consider Congressional policy set out in section 101(b) of the CWA; 3) the repeal is necessary to avoid interpretations of the CWA that push authority provided by Congress; and 4) the rule had procedural errors and lacked support on the record. The repeal puts back in place the pre-2015 definition of WOTUS.

Part of the explanation for the repeal notes that the 2015 Rule exceeded the authority granted to the agencies by Congress by adopting an interpretation of the “significant nexus” test provided by Justice Kennedy in his concurrence in Rapanos v. U.S., 547 U.S. 715 (2006). The Administration took the position that use of this significant nexus test to expand control of tributaries and adjacent wetlands resulted in regulation of waters outside of the scope of authority provided by Congress in the CWA. The agencies also stressed that District Courts had found defects in the procedure taken to pass the 2015 rule such that repealing the rule would allow greater regulatory certainty.

The definition for WOTUS will once again read as follows and be found in 33 C.F.R. § 328.3 and several other sections throughout the CFR:
(a) The term waters of the United States means
(1) All waters which are currently used, or were used in the past, or may be susceptible to
use in interstate or foreign commerce, including all waters which are subject to the ebb and flow of the tide;
(2) All interstate waters including interstate wetlands;
(3) All other waters such as intrastate lakes, rivers, streams (including intermittent
streams), mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds, the use, degradation or destruction of which could affect interstate or foreign commerce including any such waters:
(i) Which are or could be used by interstate or foreign travelers for recreational or other
purposes; or
(ii) From which fish or shellfish are or could be taken and sold in interstate or foreign
commerce; or
(iii) Which are used or could be used for industrial purpose by industries in interstate
commerce;
(4) All impoundments of waters otherwise defined as waters of the United States under
the definition;
(5) Tributaries of waters identified in paragraphs (a)(1) through (4) of this section;
(6) The territorial seas;
(7) Wetlands adjacent to waters (other than waters that are themselves wetlands)
identified in paragraphs (a)(1) through (6) of this section.
(8) Waters of the United States do not include prior converted cropland. Notwithstanding
the determination of an area’s status as prior converted cropland by any other Federal agency, for the purposes of the Clean Water Act, the final authority regarding Clean Water Act jurisdiction remains with EPA.
Waste treatment systems, including treatment ponds or lagoons designed to meet the
requirements of CWA (other than cooling ponds as defined in 40 CFR 423.11(m) which also
meet the criteria of this definition) are not waters of the United States.
(b) The term wetlands means those areas that are inundated or saturated by surface or
ground water at a frequency and duration sufficient to support, and that under normal
circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil
conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.
(c) The term adjacent means bordering, contiguous, or neighboring. Wetlands separated
from other waters of the United States by man-made dikes or barriers, natural river berms, beach dunes and the like are “adjacent wetlands.”
The term high tide line means the line of intersection of the land with the water’s
surface at the maximum height reached by a rising tide. The high tide line may be determined, in the absence of actual data, by a line of oil or scum along shore objects, a more or less continuous deposit of fine shell or debris on the foreshore or berm, other physical markings or characteristics, vegetation lines, tidal gages, or other suitable means that delineate the general height reached by a rising tide. The line encompasses spring high tides and other high tides that occur with periodic frequency but does not include storm surges in which there is a departure from the normal or predicted reach of the tide due to the piling up of water against a coast by strong winds such as those accompanying a hurricane or other intense storm.
(e) The term ordinary high water mark means that line on the shore established by the
fluctuations of water and indicated by physical characteristics such as clear, natural line
impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial
vegetation, the presence of litter and debris, or other appropriate means that consider the
characteristics of the surrounding areas.
(f) The term tidal waters means those waters that rise and fall in a predictable and
measurable rhythm or cycle due to the gravitational pulls of the moon and sun. Tidal waters end where the rise and fall of the water surface can no longer be practically measured in a predictable rhythm due to masking by hydrologic, wind, or other effects.

The net effect of this repeal is that fewer waterways will receive federal pollution protection. Many farmers and other small landowners balked at the 2015 revisions since it put a greater number of waterways in federal control and thus required federal permits before certain actions could be taken. The rescission will put the responsibility for protection of many waterways back onto states and tribal governments and thus lead to less uniformity of protection from pollution.