"Māori has a significant role to play in that service delivery," Nepia said.
"There are lots of opportunities for iwi and hapū.
"The decision for Māori is empowering, demystifying, supporting co-governance and ensures these water service entities are competent, active Treaty partners and that iwi and hapū are actively participating in the design, development, implementation and monitoring all steps of these new entities.
"The last pou is that iwi Māori are supported with information and resources to actively fill the roles anticipated.
"There are some real opportunities, economic, co-investment, that will develop and form up as we move into the transition stage.
"What I see in the reform from a Māori view is putting the WAI first."
Having worked across the iwi resource and environmental planning space and also been the interface between iwi and local and central government, Nepia arrives at her new role from the Tūwharetoa Māori Trust Board.
Her appointment follows those of Hamiora Bowkett and Heather Shotter as executive directors to the Three Waters reform programme and the announcement of the Three Waters National Transition Unit Board, to be chaired by Sir Brian Roche.
Nepia, 45, said having lived and worked on her whenua on the lake with her people, it was time to give back to the wider Māori community.
"I have spent a lot of my career based around iwi/hapū resource and environmental management and the interface of local councils, third party developers and iwi.
"I started with DIA in October last year as its partnership director, which was the interface between DIA and councils."
She said more councils were becoming receptive to Māori views and open to a solid working relationship with mana whenua.
"This was not the case 20 years ago. It was adversarial.
"I'm not saying those struggles between iwi and councils are not there but iwi have been consistent that we are not going anywhere.
"Iwi want a thriving community, as much as councils do."
Nepia said explaining why the Three Waters reforms is vital can be a tough sell because everyone has a view. Some councils, she said, were more resistant than others.
"This is one of the most significant reforms for local government and I appreciate that change is hard but the status quo could not continue.
"The case for change was made and it is about how do we all – as New Zealanders - move forward.
"That's where iwi are first movers for an intergenerational view."
•