ef·​flu·​ent | \ ˈe-ˌflü-ənt How to pronounce effluent (audio) ; e-ˈflü-, ə- \

Definition of effluent

 (Entry 1 of 2)

: flowing out : emanating, outgoing an effluent river



Definition of effluent (Entry 2 of 2)

: something that flows out: such as
a : an outflowing branch of a main stream or lake
b : waste material (such as smoke, liquid industrial refuse, or sewage) discharged into the environment especially when serving as a pollutant

Did you know?

Effluent comes from the Latin verb effluere, "to flow out". In an older meaning, an effluent was a stream flowing out of a river or lake. But nowadays effluent almost always means wastes that pour into our water and air. Liquid factory waste, smoke, and raw sewage can all be called effluents. An effluent filter keeps treated waste flowing out of a septic tank from clogging up its drainage pipes.

Examples of effluent in a Sentence

Noun The factory has been accused of discharging effluent into the river.
Recent Examples on the Web: Adjective One prong involves the agency’s decision to issue the permit without setting specific effluent limits on mercury and other pollutants. From Usa Today Network And Wire Reports, USA TODAY, 21 Apr. 2022 The soil under its 2.7 million South Florida residents allows septic tank effluent to reach groundwater, a problem intensified by climate change. Jim Morrison, Anchorage Daily News, 13 Apr. 2022 Utah’s scientific community, however, fears island building could compound the lake’s ecological problems stemming from invasive plants and fish, a legacy of effluent dumping, algal blooms and a loss of native biodiversity. Brian Maffly, The Salt Lake Tribune, 8 Mar. 2022 On the west side of Phoenix, for example, effluent from a wastewater treatment plant pours into the Tres Rios Wetlands, covering about 700 acres along the Salt River. Ian James, AZCentral.com, 8 Sep. 2021 That’s necessary to protect the environment as effluent treatment prevents the discharge of hazardous substances that can contaminate ground water and cause illnesses and other issues. Forbes, 1 Sep. 2021 But if Chicago were allowed to discharge a portion of its highly treated, if not Perrier-pure, effluent into the lake — as do Milwaukee, Toronto, Detroit, Cleveland and every other major Great Lakes city — the project's cost would plummet. jsonline.com, 2 Sep. 2021 For instance, the company upgraded its effluent treatment plant with new technology from the U.S. Forbes, 1 Sep. 2021 That same high water also threatened Conneaut’s sewer plant, which discharges treated effluent into a channel that connects to the lake. Peter Krouse, cleveland, 20 Aug. 2021 Recent Examples on the Web: Noun Aside from putting septic effluent into Utah’s water supply, the Pacific pipeline is probably the most far-out item on the list. Brian Maffly, The Salt Lake Tribune, 19 May 2022 The effluent is to be released into the soil in 1-foot intervals, rotated through 16 zones. Brian Maffly, The Salt Lake Tribune, 5 May 2022 For example, 29% of wastewater effluent is now reused in the South Coast region, while only 9% of wastewater is recycled in the Bay Area. Ian James, Los Angeles Times, 12 Apr. 2022 And high nitrogen levels caused by effluent from four sewage treatment plants were killing off fish and other creatures. New York Times, 1 Apr. 2022 The effluent, along with uncontrolled industrial and agricultural runoff, degraded the water quality with nutrients and heavy metals. Brian Maffly, The Salt Lake Tribune, 31 Mar. 2022 My group first watched a video, which explained that the plant’s effluent would be released into the Chicago Sanitary and Ship Canal, a thirty-mile-long waterway built in the late nineteenth century to rid the city of its ordure. Elizabeth Kolbert, The New York Review of Books, 9 Feb. 2022 Residents of Likely are concerned for their health and economy in the wake of the breach, which released more than 2,000 football fields worth of effluent into waterways used for fishing, bathing, and drinking water. Hannah Weinberger, Outside Online, 6 Aug. 2014 Where is the effluent flowing into the Fort Morgan plant originating? al, 25 Feb. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'effluent.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of effluent


1726, in the meaning defined above


1859, in the meaning defined above

History and Etymology for effluent


Latin effluent-, effluens, present participle of effluere to flow out, from ex- + fluere to flow — more at fluid

Learn More About effluent

Time Traveler for effluent

Time Traveler

The first known use of effluent was in 1726

See more words from the same year

Dictionary Entries Near effluent




See More Nearby Entries 

Statistics for effluent

Last Updated

29 Apr 2022

Cite this Entry

“Effluent.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/effluent. Accessed 28 Jun. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon


Test Your Vocabulary

Name That Food

  • a-light
  • Name these cookies!
Spell It

Can you spell these 10 commonly misspelled words?

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!