Due to the reform of regulatory standards councils will need to adhere to, the review's forecast for investment in Three Waters infrastructure is estimated to double since Hawke's Bay councils' 2018-2028 Long Term Plan from $313m to $605m.
The Morrison Low review found that making no changes to Three Waters delivery is not affordable or sustainable.
The review recommended an asset-owning, council-controlled organisation as the preferred Three Waters service-delivery model.
This would see the formation of a joint committee between Hawke's Bay's councils and Māori in a co-governance model.
The review found it was the best option to address affordability and the risk that the scale of investments required to meet new regulations is greater than forecast.
Wairoa mayor Craig Little said the recommended model is similar to the model that the Government prefers.
The councils believe that due to their independent review they are well positioned and informed for national reform discussions and engaging with the Government on solving challenges that come from the regionalisation of Three Waters services and their costs.
But the regionalised model does bring some challenges.
Keeping the costs of Three Waters services to an affordable level across Hawke's Bay means Napier ratepayers may pay more for Three Waters than they otherwise would.
Napier Mayor Kirsten Wise said the other significant challenge in the reform process for Napier was the commitment the council has made to investigate a chlorine-free drinking water network.
"It's vitally important that we get that reassurance from central government that within a regionalised model there will still be the ability to have different levels of service."
Wise said she would be a "broken record" continuing to ask that Napier will be able to choose to go chlorine-free in every step of the reform process.
A Hawke's Bay Three Waters spokesperson said the Government is yet to confirm the detailed process for engaging with councils as part of the reform programme.
"Government now have a copy of our report and Hawke's Bay will be sharing our findings and in particular the key challenges with regionalisation that will require Government support and investment to address."