Which of the following is a source of wastewater?

All of the above

The correct answer is option 4. All of the above.

Hospitals, industries, and households are all regarded as sources of wastewater. Between the site of production and the point of disposal, or wastewater treatment facility, sewage travels through a network of large and small pipes known as sewers. Sewerage refers to the transportation system formed by this network of large and small pipes.