cesspit; cesspool
A pit or tank for collecting sewage or wastewater. Often used in contexts of sanitation or environmental engineering.
There was a cesspit in the yard of the old house.
It's better to hire a professional to clean the cesspool.
Standard spelling using だめ for the second part.
Alternate spelling with the kanji 溜め; less common but still used.
Compound of 汚水 (osui, 'sewage, dirty water') and 溜め (tame, 'accumulation, pool'), from the verb 溜める (tameru, 'to accumulate').