Diocletian'a aqueduct, over 9 kilometres long, led water from the source of the Jadro River to the Palace. Thanks to the restoration in the end of the 19th century it is still well preserved and functioning in its greater part, except the last 3 kilometres. Municipal infrastructure improvements are used to explore this part of the aqueduct. The castelum aquae was probably north of the Palace but it has not yet been discovered although it was likely demolished when the baroque bastions were built. A greater part of the sewage system inside the Palace has been explored. This system was washed with the surplus water from the aqueduct. Channels pass beneath the streets of the northern part of the Palace, the cardo and the decumanus as they descend toward the west. It is established that the highest point of the channel is in the northeast and main channel exits the Palace below the western gate and turns to the south where it ends at the sea.

Arhitektura i urbanizam