From 1 July 2026, Tiaki Wai has taken over responsibility for the provision of drinking water, wastewater and stormwater services for the metropolitan Wellington area.  

Simpson Grierson advised on the preparation of the joint Wellington Regional Water Services Delivery Plan and was then engaged to support the formal legal establishment and transfer processes from September 2025.

The firm provided multi-disciplinary advice, including on decision-making processes, a fit-for-purpose corporate governance framework, capital structuring, the transfer of assets, liabilities, land, approvals and other matters from the shareholding councils, the establishment of a new financing programme and various operational matters to support Day 1 readiness.

The transaction is one of the first under the Local Water Done Well policy framework. It required the alignment of decision-making and transfer mechanics across five councils and the incoming Tiaki Wai Board. Our team was proud to support the Board, new Chief Executive, Mike Brewster, and the wider Establishment Team, led by Programme Director Dougal List, in advising on this complex transaction.

A landmark project for Wellington

The establishment of Tiaki Wai involved the transfer of approximately $9 billion in water assets, and approximately $1.7 billion of water debt, from the five shareholding councils to Tiaki Wai.

Planning and Environment Partner, Mike Wakefield, who led the Simpson Grierson team, noted that the complex transaction, which involved a number of the firm’s practice areas, required strategic internal coordination and substantial engagement across council shareholders, mana whenua partners, the establishment team, council staff and other advisers.

“We are proud to have been at the leading edge of this significant change for water services delivery in Wellington. Establishing Tiaki Wai as a new asset-owning water organisation for the Wellington metropolitan area will support a stronger, more robust, water service delivery model that will, over time, achieve the resilience and service improvements that the Board, shareholders, mana whenua partners and communities served by Tiaki Wai want,” says Mike.

Simpson Grierson is looking forward to continuing to support Tiaki Wai as the organisation moves into its operational phase.

New Zealand's leading water reform practice

Simpson Grierson is advising on water reform and water organisation establishment across the country, supporting both establishment teams and shareholder councils, including those involved in the recent establishment of Selwyn Water, Waikato Waters and IAWAI. The firm also advised on Watercare’s marquee financial separation from Auckland Council in 2025.

In addition to reform work, the firm has advised on some of New Zealand's largest water infrastructure projects, including Watercare's Central Interceptor, and has a large team advising on the implementation of all aspects of the new Local Government (Water Services) Act 2025.

Water governance

Simpson Grierson recently partnered with Water New Zealand to develop the Water Governance Directors' Handbook, a practical guide to support organisations navigating governance responsibilities across drinking water, wastewater and stormwater services. Download the free handbook here.

Simpson Grierson team supporting Tiaki Wai

Planning and Environment: Mike Wakefield (Partner), Padraig McNamara (Partner), Ash Cornor (Senior Associate), Graeme Palmer (Special Counsel), Judith Cheyne (Senior Associate), Jack Apperley (Solicitor).

Corporate: Don Holborow (Partner), Anastasiya Gamble (Partner), Amanda Stephenson (Senior Associate), Dania Alsagoff (Senior Associate).

Real Estate: Donna Hurley (Partner), Natalie Wilson (Senior Solicitor), Lucy Scottwood (Solicitor), Ben Gardiner (Solicitor)

Employment: Bronwyn Heenan (Partner), Ashleigh Inder (Senior Associate), Mike Mercer (Senior Associate).

Construction: Lisa Curran (Partner).

Banking and Finance: Josh Cairns (Partner), Matt Mazenier (Senior Associate), Zelda Gower (Senior Associate), Katie Daly (Solicitor), Pippi Priestley King (Solicitor).