Swift-water rescuer Michael Plumb is one of 10 Queanbeyan SES workers who have been helping with heavy flooding in Central West NSW, while their ACT counterparts remain on standby to assist if needed.

He said the six-hour stand-off involving emergency services and police was the most challenging rescue he's ever undertaken, because the man stuck on top of his car did not want to be rescued.

"He was in the middle of the causeway and was going to try to walk out because he didn't want to put anyone else in danger by rescuing him," Mr Plumb said.

"We eventually talked him out, but none of the rescuers there had ever been through anything like that."

Queanbeyan SES had workers in Forbes, Condobolin and Cowra supporting rescues and helping with flood mitigation efforts.

Meanwhile, Yass was declared a natural disaster zone on Wednesday.

Recent storms and flooding had caused hundreds of thousands of dollars worth of damage to roads, sewerage, water-supply equipment, buildings and parks.

The declaration makes Yass Valley Council one of 21 local governments to receive disaster relief funding from the NSW government.

SES members have been busy preparing for the downpour of up to 45 millimetres on rain on Thursday, expected to add to the damage already caused by months of above-average rainfall.

Queanbeyan SES public information officer Brent Hunter said about 100 workers were preparing to lay sandbags to protect properties and repair leaking roofs while keeping an eye on the Queanbeyan River and Googong Dam, which was almost at capacity on Wednesday afternoon.

An ACT SES spokesman said Canberra had extra volunteers on call to travel interstate and had been running extra training for storm or flood damage responses.

"Canberra is lucky to be a well-planned city, so we don't see as much devastation as other areas around Australia," he said.

"Our flooding tends to be more 'nuisance' flooding where water flows over low-level crossings and sometimes over roads."

He said workers had a "considerably busier year" than usual due to Canberra's third wettest winter followed by possibly the rainiest September on record.

So much wet stuff has taken its toll on roads, director of ACT roads Tony Gill said.

He had received a 30 per cent rise in reports of pot holes between June and August than in 2015, as well as more residential flooding and stormwater damage.

The SES has the following advice to cope with the upcoming wet weather:

Given that it's school holidays, parents and carers should educate their children about the dangers of riding, walking, playing and driving through flood water. Typically flood waters are dirty, which makes it difficult to see what is below the surface and they can be full of unknown debris. Flood waters can run fast and the debris may be a danger to cars and people.

Clear the gutters of leaf litter and other debris to stop water from entering the roof cavity.

Ensure yard is tidy by trimming trees and bushes and clearing any debris from the yard to ensure that during windy conditions debris is not picked up by the winds and damaging other property or people. Cleaning the leaf litter from the yard may also help reduce the detritus going into drains and through our stormwater system.

During high-wind events don't park or stand under trees. During windy conditions trees may fall over due to the extra-wet ground and tree branches can become dislodged.

It is also a good idea to know you neighbourhood and keep an eye on your neighbour. Reporting early may help with efforts to assist in property repair. Knowing how water flows in your neighbourhood is also a good idea so you will know if you have nuisance flooding or not and how to avoid it.

Don't attempt to drive, walk or ride through flood waters.