The term "foul water drain" refers to a type of drainage system that collects and redirects wastewater from households and industries. Synonyms for foul water drain include sewage system, wastewater system, sewerage system, drainage network, and wastewater treatment system. Another synonymous term for foul water drain is sanitation system, which encompasses both the collection and treatment of wastewater to prevent environmental contamination and public health hazards. Other related terms include greywater system, which refers to the collection and reuse of non-toxic wastewater for irrigation and other non-potable uses, and stormwater drain, which collects and redirects rainwater runoff. In all cases, proper maintenance of these systems is crucial for ensuring the health and safety of both people and the environment.