From November 1, level 4 water restrictions will come into force in Dubbo, just weeks after the definition was drawn up by the local council.

Dubbo Regional Council mayor Ben Shields said following record low rainfall and virtually non-existent inflows into the regions main water supply at Burrendong Dam, this extreme step was essential to ensure every last drop of water is saved.

"Level 4 is quite an extreme level to go to: no watering outside effectively, even some evaporative air conditioners cannot be used at night," he said.

"I'm quite relieved that we are moving to these regulations… it's essential that we go down this [path]."

This is the first time water restrictions have been enforced to such an extent in Dubbo, with council redesigning its drought management plan to include new classifications up to level 6 and new definitions for what each level entails.

Cr Shields said a $250,000 education campaign would also be rolled out in coming days to inform the community about what will be expected.

"Dubbo has never really had water restrictions to this extent before so they don't really understand it."

Different story next door

Meanwhile, in nearby Mudgee, water restrictions remain at level 1, are at level 4 in Orange and there are currently no restrictions in place in Gilgandra.

"The community is already using less water without council [intervention] and are being responsible about how they use water," said David Neeves, general manager of Gilgandra Shire Council.

"We're keeping a close eye on it and naturally as we come into the summer months if we haven't had rain we'll need to reconsider."

NSW has no standard classification system for water restrictions, leaving it instead to local water utilities, which are in most cases local governments, to manage water allocated from state-owned corporation WaterNSW.

However, WaterNSW does manage dams and river systems across the state and was tasked with providing a report to the NSW government looking into future rural infrastructure investment options.

The Guardian reported one such option was to consider diverting water away from the coast and into drought-stricken inland regions, a proposal first considered and subsequently rejected by John Bradfield in 1938.

"I find that absolutely amazing that there isn't a standardised set of what the restrictions mean," said Dr Ian Wright, a senior lecturer in Natural Science at Western Sydney University.

"Victoria has a state wide plan, they have a state drought plan, they have definitions for everything so its quite clear."

Statewide system necessary

Upper Macquarie irrigators welcomed the level 4 restrictions introduced by Dubbo Regional Council, but said a standard statewide classification system was a necessary next step.

"I think that if we had a standardised system that would only help in communities understanding, businesses understanding, people's understanding of what their obligations are," said Peter Schuster, chair of the Upper Macquarie Groundwater Group.

"We are heavily regulated as groundwater users, we adhere to a water sharing plan, we're here to work with council and others to get through this unprecedented drought."

Burrendong Dam, which supplies water to the Dubbo region is down to 4.4 pe rcent. ( ABC Western Plains; Jennifer Browning )

NSW Water Minister Melinda Pavey said she was not yet convinced of the idea.

"Now is not the time to come in and take over, it's about working in collaboration," she said.

"We are in uncharted territory because we are off the charts in terms of the lack of rain."

Dubbo mayor Ben Shields disagreed, arguing that now was precisely the time to be having such conversations.

"The thing that will disappoint me the most out of all this is if we come out the other end of this drought and we haven't actually made serious, long-term changes," he said.

"It is very confusing. If everyone was on the same system, it would be a lot better."