Bone dry conditions have forced the NSW Rural Fire Service (RFS) to bring forward the start of the season to September 1 - a month ahead of schedule, and with no rain on the horizon it is urging residents to be vigilant.

More than 50 fires were burning across NSW on Friday, including one at Martins Creek and another at Lambs Valley.

Torched stolen cars, fallen power lines, lightning strikes and arson are the biggest threats, along with property owners who light a fire that becomes out of control.

"We've had little to no rain over winter and the dryness of our bush fire fuels is a worry," district manager for Lower Hunter Superintendent Martin Siemsen said.

"Leading into spring and summer we are known to have weather that is conducive to bush fires and the long term forecast is not looking good."

Hunter Water has confirmed Level 1 water restrictions will be enforced in the Hunter region from September 16, with the combined total dam storage now sitting just above 60 per cent.

Superintendent Siemsen could not put a figure on how much water the RFS used to extinguish an average fire. Each one is very different.

He said ground and aerial crews used "a lot of water" and each RFS vehicle could carry up to 3000 litres, depending on its size.

If a fire does break out firefighters may be forced to take water out of a farmer's dam - even if there are livestock that rely on it.

The RFS has access to underground water, Hunter Water's network and RFS specific water tanks but it's not always possible to stick to these resources.

"A better option is to find a water source that doesn't affect the property owner," he said.

"But that's not always possible.

"If we need to take water out of a dam we note the location of that dam and have a conversation with the property owner before we use the water.

If we do take water off property owners who have livestock we can replenish what we have taken through a program with the NSW Department of Primary Industries."

Superintendent Siemsen said a number of factors dictated water usage.

"It depends on the fire, the type of resource you have fighting the fire, how big the fire is and if the fire is developing," he said.

"We use quite a lot of water to extinguish a fire which is why we are urging people to be prepared and vigilant and we are urging them to be careful when lighting and monitoring a fire.

"Prevention is definitely better than a cure, as they say, and we want to try to prevent as many fires as possible."

For information about preparing for a bush fire, and creating a survival plan, go to www.rfs.nsw.gov.au