Cesspools

A cesspool, also known as a cesspit, is an underground chamber used to receive wastewater from a building. It is typically a single large receptacle, often masonry, concrete, or a lined pit, that collects blackwater and greywater. Unlike a septic tank, a cesspool provides little or no wastewater treatment; liquids permeate the surrounding soil through the walls or bottom, while solids accumulate as sludge at the bottom.

Construction and operation vary, but the common principle is that wastewater is discharged into the chamber and only a portion is treated by the surrounding soil. Over time, solids accumulate, reducing capacity and increasing odors and the risk of backups. The system’s performance depends on soil permeability, groundwater level, and proximity to wells or watercourses. Poorly sited or poorly maintained cesspools can contribute to groundwater contamination and public health risks.

Regulation and replacement: in many regions, cesspools are subject to permits, inspections, and pumping requirements. Many jurisdictions encourage upgrading to a septic system or connecting to a municipal sewer to provide proper wastewater treatment and protect water quality. Abandonment typically involves emptying and sealing the pit, removing remaining contents, and filling the chamber to prevent collapse. Cesspools are less common today and are increasingly replaced by systems designed to treat wastewater before it reaches the environment.