Commerce Commission tightens oversight of Wellington water provider Tiaki Wai

Commerce Commission Chair John Small said the additional regulation will help build a clearer picture of Tiaki Wai's current performance and if the money it plans to spend will deliver value for money to consumers.

"Good regulatory decisions depend on good information. Our priority is to establish a clear understanding of where Tiaki Wai is at now so we can provide effective oversight and support better outcomes over time."

The Commission said the new requirements would provide councils, consumers and other stakeholders with greater visibility of how services are performing, where investment is being directed, and whether promised improvements are being delivered.

More detailed reporting on faults, maintenance and network performance will make it easier to track whether services are improving. Independent expert reviews will provide assurance that major investments are necessary, represent value for money and can realistically be delivered.

Small said the changes were about more than simply increasing reporting requirements. "By combining greater transparency with independent expert scrutiny and ongoing monitoring, these measures will strengthen confidence in Tiaki Wai's performance and decision-making."

The Commission described its approach as targeted and proportionate, focusing on areas where stronger oversight is most likely to improve outcomes for consumers.

The Commission acknowledged that Wellington households are facing the prospect of higher water costs as investment in the region's ageing infrastructure gathers pace.  Small said, “Consumers want confidence that investment is being directed to the right priorities and that promised improvements are being delivered. We will take an active role in monitoring Tiaki Wai's performance, closely review the information it reports, and focus our efforts where greater oversight can have the biggest impact." 

"When consumers are being asked to fund significant investment, they need confidence that every dollar is being spent wisely," Small said. "Our role is to make sure there is robust information, strong accountability and independent scrutiny behind those decisions, so consumers can have greater confidence that investment is delivering better, more reliable water services over time."

Background

The Commerce Commission was established as the economic regulator for the water sector in August 2025. 

From its inception on 1 July 2026, Tiaki Wai is subject to economic regulation and must comply with information disclosure (ID) requirements for all regulated water service suppliers. These ID requirements were introduced under the Commerce Act.  
 
Under the additional information disclosure requirements Tiaki Wai will need to: 

• Regularly report information on network fault attendance and resolution, and network maintenance spending. Over time this will give consumers a clearer picture of whether services are improving.
• Assess its asset management capability and publicly report on plans to strengthen this. 
• Allow independent experts to assess key plans and forecast expenditure to provide assurance that investment is targeted to the right priorities, represents value for money and can realistically be delivered.  

For consumers this means:

• More information about service reliability and performance.
• Independent scrutiny of major spending plans.
• Better visibility of whether promised improvements are being delivered.
• Greater accountability for investment decisions.