Explanation:

A sewer which receives the discharge of a number of house sewers is called a lateral sewer. Here are some details about lateral sewers:

- Definition: A lateral sewer is a type of sewer that collects wastewater from multiple house sewers and carries it to a main sewer, interceptor sewer, or treatment plant.

- Purpose: The purpose of a lateral sewer is to transport domestic wastewater, including sewage and greywater, from individual homes or buildings to a larger sewer system.

- Characteristics: Lateral sewers are typically small in diameter, ranging from 4 to 12 inches, and are buried underground. They are usually made of PVC, clay, or concrete pipes and are designed to have a slight slope to facilitate the flow of wastewater.

- Maintenance: Lateral sewers require regular maintenance to prevent clogs and backups. Homeowners are responsible for maintaining the portion of the lateral sewer that runs from their property to the connection point with the main sewer.

- Importance: Lateral sewers are an essential part of the wastewater collection and treatment system. Without them, individual homes and buildings would need to have their own septic systems, which can be costly and environmentally damaging if not properly maintained.

In summary, a lateral sewer is a small sewer that collects wastewater from multiple house sewers and transports it to a larger sewer system. It plays a critical role in the collection and treatment of domestic wastewater.