The NSW State Emergency Service said there had been more than 50 calls for help since 1.30pm today after flash flooding hit the town from the Central Highlands.
Crews are coming in from Bathurst, Orange and Blue Mountains to respond to calls for help.
Homes and businesses were inundated by the flash floods.
Residents and emergency services can be seen sweeping up the floodwaters.
Shops, cafes, the local church and the bowling club were all inundated by the torrent.
The flooding was caused by heavy rain around 1.30pm today.
More than 72 millimeters were recorded in Lithgow, nearly a month of rain in just over an hour.
Several rescues were carried out by the emergency services.
A man was rescued from his car in deep flood water by a tractor on Barton Street.
The water has now receded from most places in Lithgow and some roads have reopened, but cleanup is now underway.
Inside a ‘hellish’ battle to contain WA’s bushfires