Crews shut down the water line and were expected to be working on repairs "well into the night," according to a spokesperson from Padre Dam Municipal Water District.
Water officials said they had been working on a new main in the area on Wednesday. Residents had already spent most of the day Wednesday without water.
Water is expected to be back up and running by midday Friday.
The cause for the break and the amount of water lost is not yet known.
Prospect Avenue was still closed to traffic while Padre Dam Municipal Water crews worked to replace the main.
Drivers were advised to avoid the area.