Collective sanitation becomes mandatory when homes or structures can be connected to the public network.
The connection system collects and transports a municipality's wastewater to treatment plants, where blackwater (from toilets and urinals) and graywater (from kitchens, sinks, washing machines, etc.) are treated before being discharged into the natural environment.
Agricultural and industrial activities also generate wastewater; the water is often used in manufacturing processes or to clean equipment and buildings. Wastewater from these operations therefore has specific characteristics that distinguish it from domestic wastewater.
