Evolution of the Clean Water Act

By Isabelle Bienen, NWNL Research Intern
(Edited by Alison M.  Jones, NWNL Director)
All photos © Alison M. Jones

Isabelle Bienen is at Northwestern University studying Social and Environmental Policy and Legal Studies. As a NWNL summer intern, she wrote 5 blogs on the 1972 US Clean Water Act [CWA] and its role in NWNL’s 3 US watersheds. This – her 4th blog – explains the Clean Water Act and subsequent rulings. Her earlier CWA blogs: CWA in Mississippi River Basin, CWA in Columbia & Raritan River Basins & CWA and Health IssuesAll rivers shown below (excluding the ditch) are Waters of the US [WOTUS] covered by the CWA.


Jones_140516_ID_7351.jpgA Hells Canyon reach of the Snake River, a Columbia River Basin tributary

Clean Water Act (1972)

A 1960’s growing concern over the need to control water pollution led to the 1972 Clean Water Act [CWA], as noted in the first NWNL blog of this series. The 1972 CWA (originally, Federal Water Pollution Control Act) established a structure for Federal regulation of pollutants discharge into US surface waters. [It does not apply to well water or aquifers].  The CWA prohibits any individual, unless permitted, to discharge pollutants from point sources (versus broader nonpoint sources) into Waters of the United States [WOTUS].

Point pollution sources are specific, identifiable entry points of pollution, i.e., ditches or pipes that dump pollutants from one specific spot directly into a navigable waterway. Notably, the 1972 Act did not address or allow for control of nonpoint pollution sources, i.e. runoff from rural farmland, urban storm/sewage, construction sites or forests .1 (Nonpoint pollution would be addressed in 1977, and again in 1987.)

Jones_150726_NJ_3553.jpgConfluence of North and South Branches of the Upper Raritan River Basin

Changes and Amendments to the Clean Water Act of 1972

  • WOTUS Rule-1977 (nonpoint pollution regulations & WOTUS definition)
  • Municipal Wastewater Treatment Construction Grants-1981
  • CWA Amendment-1987 (transfer of control to states and tribes)
  • Clean Water Rule-2015 (definition of  1972 CWA & WOTUS-1977 coverage)
  • Steps One & Two-2017 (repeal & revision of Clean Water Rule-2015)
  • Applicability Date Ruling-2017 (setting pre-2015 rules until new 2020 rule)

Both the WOTUS-1977 and -2015 rulings were outlined to clarify the original CWA. Basically, they addressed existing confusion over the term “navigable waters.”9

The CWA defines ‘navigable waters” as “waters of the United States, including the territorial seas.” But “waters of the United States” is not specifically defined in the CWA. Court decisions, regulations and agency policies have established that “waters of the United States” applies only to surface waters, not groundwater, including rivers, lakes, estuaries, coastal waters, and some wetlands. In inland areas, those waters include:

  • All interstate waters;
  • Intrastate waters used in interstate and/or foreign commerce;
  • Tributaries of the above; and
  • Wetlands adjacent to all the above.

The law is less clear in regard to smaller streams, ephemeral water bodies, and wetlands not adjacent to other waters of the United States. While groundwater is not included as a navigable water, discharges to groundwater, directly connected to a surface water, are sometimes included in NPDES permits. [NPDES: EPA’s National Pollutant Discharge Elimination System.]

Jones_070625_WA_4649.jpgThe Columbia River in Washington State, across from Hanford Nuclear Site

Waters of the US Rule [WOTUS]-1977

The term WOTUS and its regulatory scope were first developed in 1977, five years after the Clean Water Act addressed the need for protection and inclusion of all “navigable water.” WOTUS-1977 attempted to define “navigable waters” so as to establish the Act’s jurisdictional scope. It addressed tribal and state certification programs, polluting permits, and waste-spill prevention.6

Water Quality Act-1987 gave control to the States

In 1987, CWA changed responsibility for water-quality regulation, implementation and monitoring from federal to individual state control. This switch was built on the EPA’s established state partnerships and the Clean Water State Revolving Fund.1 CWA regulations were set up state-by-state; yet the EPA kept the authority to step in if water-quality standards were not being met.

Jones_111027_LA_0832.jpgLake Martin in Atchafalaya Basin, Louisiana

Clean Water Rule-2015 re-defined “Waters of the US” 

Congressional debates had underlined the vagueness of the term “navigable waters,” in WOTUS 1977.  The Supreme Court decisions of 2001 and 2006 attempts to clarify WOTUS (1977) were insufficient; and the definition regarding the nation’s authority over streams and wetlands remained vague

Thus, the purpose of Clean Water Rule-2015 was to reframe the existing ambiguity.  It stated that any waterway that has a “significant nexus with navigable water” falls under CWA regulations. Monitoring and controls would apply “when any single function or combination of functions performed by the water, alone or together with similarly situated waters in the region, contributes significantly to the chemical, physical or biological integrity of the nearest traditional navigable water, interstate water or the territorial seas.”

Jones_170610_NE_3515.jpgThis Missouri River Basin farm ditch is “non-navigable waterway” excluded by the CWA

“Navigable waters,” according to an American Rivers summary of  Clean Water Rule-2015, include “traditional navigable waters, interstate waters, and all other waters that could affect interstate or foreign commerce, impoundments of waters of the United States, tributaries, the territorial seas, and adjacent wetlands.”2 Clean Water Rule-2015 limits pollution in 60% of the nation’s waterways.3

There are, however, limits to what the 2015 Clean Water Rule regulates. It didn’t regulate  smaller water systems surrounding river basins, nor smaller bodies of water that eventually run into oceans or protected basins, despite their endpoints. For instance, a cloud of confusion remained over whether or not wetlands adjacent to non-navigable tributaries to navigable waters were protected.

In May 2015, the EPA and Army Corps of Engineers released Clean Water Rule-2015 as a 297-page modification to  CWA (1972) and its follow-up Waters of the US Rule/ WOTUS-1977. The 2015 rule upheld much of WOTUS-1977, but only after extensive consideration of previous Supreme Court rulings, intensified public concern and countless meetings with farmers and others in the agricultural industry.

This lengthy examination period, prior to finalizing Clean Water Rule-2015, included a study of a January 2015 EPA publication titled “The Connectivity of Streams and Wetlands to Downstream Waters: A Review and Synthesis of Scientific Evidence.” This report studied 1,200 peer-reviewed publications on the connectivity and isolation of US waters. It was compiled to inform the 2015 rule-making process by the EPA and Army Corps of Engineers as it further defined WOTUS. A significant conclusion of their Connectivity Study was: “Streams, regardless of their size or how frequently they flow, are connected to and have important effects on downstream waters.”2

Jones_110729_NJ_0133.jpgSouth Branch of the Upper Raritan River Basin, New Jersey

The EPA spent over a decade examining studies and holding debates to provide strong clarification of the 2015 Rule. While still applying pollution controls to large lakes and rivers, the 2015 Rule also gave the EPA control over ponds, intermittent and ephemeral streams, and other small waterways that impact and connect to larger navigable water systems. Smaller waterways were now to be protected.3 After the EPA released its final version of this rule, President Obama stated, “This rule will provide the clarity and certainty [that] businesses and industry need about which waters are protected by the Clean Water Act; and it will ensure that polluters who knowingly threaten our waters can be held accountable.”4

Clean Water Rule-2015 regulations protected waterways that supply drinking water to 1 out of 3 Americans3 by setting measurable boundaries for coverage by the original CWA-1972.  This 2015 rule actually reduces the scope EPA had the 1970’s, 80’s and 90’s, and doesn’t regulate most ditches – a controversial issue during the hearings. It excludes farms and stock ponds, grassed waterways, groundwater, shallow subsurface flows, tile trains for drainage. It does not interfere with private property rights.3 Ken Kopocis, former chairman of EPA’s water office, stated the goal of Clean Water Rule-2015 wasn’t “an expansion in jurisdiction, but instead more predictability and consistency.”5

The confusion from the non-stipulated aspects of this rule lies in whether or not the CWA protects channels through which water flows intermittently or ephemerally, or which periodically provide drainage for rainfall. The legality of this question had previously resulted in a split decision in the Supreme Court in 2006.  Thus, no direction or clarification was provided by CWR-2015 on how to implement this decision.6

Jones_070708_OR_6995.jpgColumbia River Estuary at Astoria, Oregon

Ongoing WOTUS Rulings: EPA’s Steps One & Two

In 2016, just 40 days into the Trump Administration, the EPA and USACE began withdrawing from CWR (2015) in order to create more “industrially-friendly” standards.4 The Clean Water Rule-2015 had justified broader jurisdiction based on its Connectivity Study that concluded headwater systems are connected to, and thus definitely affect, downstream waters. If EPA and USACE repealed Clean Water Rule-2015, it would seem to also refute its own extensive “Connectivity of Streams and Wetlands to Downstream Waters Report – Jan. 2015.” 3

Over a year later, in July 2017, the EPA filed several proposed changes. “Step One-Repeal of the 2015 Rule” would permanently undo the Clean Water Rule-2015. “Step Two-Revised Definition of WOTUS” would re-codify and revise pre-2015 regulatory definitions of Waters of the US [WOTUS]. The EPA intent with these proposed rules and replacement of the 2015 Rule was to loosen regulations on farmers, rangers and real estate developers on how to interact with streams and tributaries flowing across their properties.3

Jones_170612_NE_3783.jpgThe confluence of the braided Missouri and Niobrara Rivers in South Dakota

The EPA claimed this 2017 One-Step repeal would “reduce confusion and provide certainty to America’s farmers and ranchers.”7 In support, the Trump Administration stated that the 2015 Rule and WOTUS definition relied too heavily on the “Connectivity Report,”8 and science in answering policy questions. It also argued against language in Clean Water Rule-2015 and WOTUS that used the Connectivity Report’s terms such as “similarly situated.”8 The Administration’s 2017 repeal reflects opinions that said the 2015 Rule’s language for smaller bodies or connected waters was too vague.8

Jones_130518_WI_8311.jpgStoddard Pool 8 of The Mississippi River in Wisconsin

2018 Updates & NWNL Comments

Following a Supreme Court decision, the EPA announced in February 2018 that Clean Water Rule-2015 would not take effect until Feb. 6, 2020. That gave the EPA and USACE two years to redefine terms in the 2015 Rule before it would take effect. Public comment periods on three updates – the applicability date, EPA’s Step One-Repeal, and EPA’s Step Two-Revise – ended August 13, 2018.  Thus, until 2020, pollution controls will apply only to waters specified before the 2015 Rule.

In January 2018, NWNL studied the EPA’s “Consideration of Potential Economic Impacts for the Final Rule: Definition of Waters of the US [WOTUS].” This memo notes that certainty in interpretation and implementation creates greater efficiency and investment and reduces costs for “operational flexibility.”  Yet this paper acknowledges that uncertainty may persist.  EPA claims its 2-year revision period will minimize significant economic impacts “on a substantial number of small entities” and it will undertake “a fulsome treatment” of potential economic impacts.

While there may be economic benefits, NWNL notes that environmental guarantees provided by CWA-1972 and Clean Water Rule-2015 are vital to the health of Americans, US flora and fauna, oceans and thus the planet. Do economic benefits outweigh environmental safety?

The US Government is responsible for safeguarding our drinking water. Pollution controls are especially critical today, as technology and growing populations produce more toxic sewage, chemical and plastic waste than ever before. US citizens must also take individual responsibility for their health and their watersheds. We should simultaneously be conscientious stewards, responsible consumers and aware citizens actively protecting our waters. Ensuring clean water requires both bottom-up and top-down vigilance.


  1. US Environmental Protection Agency, accessed 6/19/18, published 2017, IKB, link.
  2. American Rivers: The Clean Water Rule, accessed 6/26/18, published 2017, IKB, link.
  3. New York Times, 6/26/18, published 2018, IKB, link
  4. Politico, accessed 6/26/18, published 2015, IKB, link.
  5. Environmental Protection Agency, 6/27/18, published 2015, IKB, link.
  6. American Bar, accessed 6/26/18, published 2017, IKB, link
  7. Independent, 6/27/18, published 2018, IKB, link
  8. E&E News, accessed 7/5/18, published 2018, IKB, link
  9. Red Lodge Clearinghouse, accessed 8/10/18, published 2010, AMJ, link

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