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

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

The science shows the pollution problem in Lough Neagh comes largely from agriculture, with some from wastewater processing, septic tank seepage and industrial pollution around the shores.

From BBC • Sep. 9, 2025

Initially, the fire agency reported that the woman fell into a sinkhole, but later clarified that the hole was in fact an old septic tank that was no longer in use.

From Los Angeles Times • Feb. 8, 2024

They stretched out in the middle of the road, flat on their backs, not wanting to miss anything should one of my celebrity friends decide to drop by and help me dig the septic tank.

From "Me Talk Pretty One Day" by David Sedaris

Related Words

• cesspool
• sewer