Homes and businesses were flooded in Lithgow at the weekend after a storm dumped more than 80 millimetres of rain.
The State Emergency Service (SES) says up to five centimetres of water flowed through some homes, after the storm passed over the town at around 9:30pm (AEDT) on Saturday night.
Central West Regional Controller Craig Ronan says the SES received about 20 calls for assistance.
He says the rain was extremely heavy.
"I believe it was in excess of 80mm in the Lithgow area," he said.
"I believe there was quite a bit more in the Blue Mountains, but it was the result of the low that came down the coast and storm passed and the water receded as quickly as it rose."
The SES is again urging people in the Central West not to drive into floodwaters, after the two rescue missions on the weekend.
Mr Ronan says volunteers had to risk their own safety to rescue the occupants of two vehicles in the Lithgow district.
"Just people entering floodwaters," he said.
"And again, I remind people that in severe thunderstorms, there is heavy rain.
"When that occurs, people should not enter floodwaters.
"It's fast flowing water and there's a good possibility those people may drown."
© ABC 2013
15:46 EDT The Australian research body the Climate Council has argued in its latest paper that the probability of drought will increase, and it will become more severe, because of climate change.