The city water supply system was hidden under the streetsThe city water supply system was hidden under the streets

The main pipes supplied big public buildings, like the baths, the synagogue, the public water clock, the water fountains. Only wealthy households could afford water supply. The water was diverted by the main canals by lead pipes, and was then redistributed to the mansion's kitchen, the bath, the latrine and the open air fountain.

Common households relied heavily on public fountains. The demand for fresh water was so big, that new fountains were opened constantly. To make it cheaper, people often used as building material pieces of older buildings and monuments. Such is the case of a marble altar with a votive inscription on it. A century after it was placed at a public space, the altar was taken out and reused as a water-fountain façade. It is now in the Archaeological Museum of Plovdiv.

The first layout of the streets of Philippopolis predates Roman times. However, the laying and the creation of the sewage system is an indisputable Roman contribution to the city's welfare. The fist pipes were laid underground at the beginning of the 2nd Century, when the whole city and its streets got a facelift. Another major repair was done at the end of the 3rd Century, when Philippopolis recovered after the destruction of the Goth invasion of 251. The system was abandoned by the end of the 5th century, in the troubled times when people moved to the acropolis leaving the indefensible lower parts of the city.