More than 70 people, including guest of honour Waitaki MP Jacqui Dean, attended the brief opening ceremony on the banks of the Clutha River at the site of the bore beside Old Punt Rd.
Millers Flat Water Company chairman Bruce Abbott likened the process the organising committee, and later the board of directors, went through to deal with the required paperwork and accessing funding to the journey water made from the mountains to the sea, and the hurdles it encountered along the way.
Roxburgh Community Board chairman Stephen Jeffery said the water scheme was the most significant thing to happen to Millers Flat since gold was discovered.
He said Millers Flat had a reputation for being a strong community with a strong spirit and the commissioning of the project reinforced that.
He said the potable water supply would encourage economic benefits.
"There has been renewed interest in building [homes and sub-divisons] in Millers Flat," Mr Jeffery said.
Ms Dean and Mr Abbott unveiled the plaque set in a Millers Flat rock to mark the opening.
