septic tank

American  

[sep-tik tangk] / ˈsɛp tɪk ˌtæŋk /

noun

1. a tank, often underground, in which organic sewage is decomposed and purified by anaerobic bacteria.

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septic tank British  

noun

1. a tank, usually below ground, for containing sewage to be decomposed by anaerobic bacteria

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Etymology

Origin of septic tank

First recorded in 1900–05

Example Sentences

At one point, the cave faced a potential threat when someone attempted to develop the land and convert the cave into a septic tank.

From Science Daily • Apr. 3, 2026

Tougher controls over the spreading of sewage and septic tank sludge to land as fertiliser in farming are also proposed, as are limits on using digestate from anaerobic digestion plants.

From BBC • Feb. 3, 2026

Her bathroom became a toilet she fastened on top of her septic tank outside and exposed for her neighbors to see — had any of them come back.

From Los Angeles Times • Sep. 30, 2025

There were six beds arranged in three bunk beds, and in one corner there was a septic tank and "a pipe that served as a shower".

From BBC • Jan. 8, 2025

“But only if you finish that hot chocolate. I cleaned out a septic tank to earn this money. Not that you should feel guilty or anything.”

From "Wintergirls" by Laurie Halse Anderson

Related Words

• cesspool
• sewer