How far any of them progress looks set to come down to what sort of consensus builds among elected representatives, as well as the financial case for collaborative ventures.
Five options drafted by council chief executives have been put in front of the region’s mayors and they are now expected to be discussed among councillors, fine-tuned and bolstered by financial information.
Otago Mayoral Forum chairman and Waitaki District Mayor Gary Kircher said options ranged from the status quo to water needs being met by a council-controlled organisation covering a vast area.
There would be an effort to find common ground and he expected the list of options could narrow this month.
Councils have a deadline of September 3 next year for submitting water services delivery plans to the government.
"We’re very mindful of time and we want to make sure that we use it wisely, so we’ll keep this moving quite quickly," Mr Kircher said.
Maintaining momentum was critical, he said after Friday’s forum.
Mr Kircher said councils were facing significant cost increases for water infrastructure and they had to look to limit the impact.
The Waitaki District Council might also look towards South Canterbury for alignment, he confirmed.
Exploration of options for Otago and Southland councils to work together had been happening since March, Otago Mayoral Forum minutes indicated.
This included looking into regional delivery models and shared services.
Clutha District Mayor Bryan Cadogan said scale was crucial for delivering efficiency.
He warned against settling for sub-optimal options, as ratepayers would bear the brunt if councils failed to club together, he said.
"I believe it’s our last chance," Mr Cadogan said.
"We’re at the last-chance hotel."
Any council considering just its own interests could inflict financial harm on its neighbours’ ratepayers and put potential collective gains at risk, he said.
Dunedin Mayor Jules Radich said there was a range of possibilities for the way ahead.
Details would need to be discussed, he said.
The Queenstown Lakes District Council said Mayor Glyn Lewers and chief executive Mike Theelen attended the forum in Dunedin.
No firm positions were taken and discussions would continue within each council, a spokesman said.