Economic regulation of water services: New Commerce Commission information disclosure rules

The Commerce Commission (the Commission) has finalised new economic regulatory rules relating to information disclosure for local authorities and water organisations that provide drinking water and wastewater services. Stormwater services are not subject to regulation at this stage, although there is flexibility for stormwater to be included at a later date.

Background

Amendments to the Commerce Act 1986 in August 2025, made as part of the Local Government (Water Services) Act 2025, established the Commission as the economic regulator for water services.

The new information disclosure rules, which apply from this Friday, 27 February 2026, are designed to improve transparency and accountability, by providing stakeholders with information that complements other sources, and which will allow assessments of performance across the water sector.

The final rules followed public consultation undertaken in September and October 2025, which led the Commission to make several amendments before issuing its final rules. The Commission’s final determination package can be found here.

Explainer: what are the new information disclosure rules?

The Commission has said that water and wastewater networks are critical infrastructure and that economic regulation provides an independent mechanism to scrutinise whether providers are managing those assets in a way that protects both current users and future generations.

The rules will facilitate this scrutiny by requiring regulated water service providers to publicly disclose consistent, standardised information about their performance and finances. The Commission will then analyse the disclosures made, with the aim of giving communities and consumers clearer information about, and visibility of, how water services are being delivered, including by enabling comparisons of performance across providers, and identifying trends over time.

In summary, the new information disclosure rules will require all water service providers to regularly publish key information including:

the prices charged for water supply and wastewater services;
revenue received and expenditure incurred on water supply and wastewater services; and
how providers plan to manage their water infrastructure over time.

The Commission has emphasised that information disclosure will become a core regulatory tool for identifying inefficiencies, highlighting good performance, and targeting areas for improvement.

Phased implementation

While the information disclosure rules come into force on 27 February 2026, the Commission has provided for a phasing in of the new disclosure requirements. This is to allow water service providers time to develop systems and processes that can support the disclosures.

In terms of upcoming disclosure requirements in 2026 (noting additional requirements apply in 2027 and 2028), these involve:

Start date	Frequency	Requirements
Immediate^[1]	When the requirement applies, disclose within 5, 10 or 30 working days	Statement from existing minor aspect supplier and reasons why Transfer agreement Value of assets and liabilities transferred Date of becoming or ceasing to be a regulated supplier Date of taking over the drinking water supply of another provider
30 June 2026	When the requirement applies, disclose immediately or within 10 working days	Dividends policy Policy for funding growth Information about charges Statement on becoming a minor aspect supplier

Spotlight on Wellington water services

In a separate announcement on 13 February 2026, the Commission announced that it is assessing whether additional regulation should apply to Tiaki Wai, the new water organisation that will deliver water services in the Wellington metropolitan region from 1 July 2026.

The predecessor to Tiaki Wai, Wellington Water Limited, is already subject to temporary economic regulation through foundational information disclosure, which will be replaced by the new information disclosure rules, described above.

As a prelude to how the Commission may be analysing information disclosures, in its first report on Wellington Water’s first disclosures (to 31 October 2025) it identified a number of concerns, including:

increasing reactive maintenance costs across the network;
low confidence in the accuracy of reported data; and
scope for improvement in its Culture and Value for Money Plan performance and in the clarity of its progress reporting.

The Commission has recently indicated that targeted, additional information disclosure requirements for Tiaki Wai may be appropriate, above the new national disclosure rules applying from February 2026.

What these changes mean for water service providers

Although there is a ‘phasing in’ of these new disclosure requirements, local authorities and new water organisations will need to gear up to ensure that they can comply with these new requirements. This needs to be resourced at an already busy time for the water sector, with many local authorities working at pace to achieve the transfer of responsibilities to new water organisations, and water organisations working to build a solid platform for the delivery of water services.

The full disclosure regime is expected to be in effect by the end of July 2030. For completeness, these new disclosure requirements are in addition to any existing disclosure requirements under the Local Government Act 2002, Local Government (Water Services) Act 2025, and reporting requirements on the environmental performance of networks under the Water Services Act 2021.

If any current or future water service providers would like to learn more about the new requirements and how to prepare for compliance, please contact one of our team.

Special thanks to Achi Simhony for her assistance in writing this article.

^[1]Wellington Water is not subject to immediate disclosure requirements because it continues to disclose information under Foundational Information Disclosure.