Taumata Arowai, the country's water regulator, has released its third annual report on water networks — the first to include full wastewater data from all 71 network operators, covering 84 percent of the population. RNZ

The report covers 559 public drinking water networks with 687 treatment plants and 56,000km of piping, along with 331 public wastewater networks with 318 treatment plants and 35,000km of pipes.

About 15 percent of pipes were rated in poor or very poor condition. The report says that figure is probably an underestimate.

The data showed 11,535 wastewater overflows in 2024/25 — an average of 31 a day. Average water use across the country was estimated at 678 litres per connection per day. About a third of councils had at least one drinking water network with "very high" leakage by international standards.

On the wastewater side, 22 percent of treatment plants were operating on expired resource consents — meaning their legal permission to discharge treated wastewater had lapsed and not yet been renewed. Nearly half, 48 percent, were due for consent renewal within the next 10 years. Operators took an average of five and a half years to get consents back up to date.

About 74 percent of wastewater was discharged to coastal environments. In metropolitan areas, 99.6 percent of wastewater was treated to a tertiary standard — the highest level of treatment, which uses filtration, nutrient removal and ultraviolet disinfection. But metropolitan networks also had nearly three times as many blockages per 100 metres of pipe compared with provincial and rural areas.

Taumata Arowai was set up by the then-Labour government in 2020 as part of its water reforms, following the Havelock North campylobacter outbreak in 2016 that sickened thousands. Water services had previously been regulated by the Ministry of Health. The National-led government kept Taumata Arowai after taking office, while scrapping the earlier Three Waters delivery model. Dr Sara McFall, Taumata Arowai's head of systems, strategy and performance, is associated with the report's release.

The broader regulatory context matters here. Taumata Arowai's own publications over the past two years have flagged pressure problems in pipes — where water pressure drops low enough that contaminated water can be drawn into the drinking water supply from household or business connections. Its Network Environmental Performance Report 2023/24 found some operators reporting very high pressure that can cause more pipe bursts, especially in older networks. An Early Insights document published in April 2026 noted some drinking water systems operating under low reference pressure.

Those pressure and leakage findings take on a sharper edge against the pipe-condition data in this report. If 15 percent of the network is already in poor or very poor condition, and the report itself says that is likely a floor rather than a ceiling, then the consent-renewal backlog compounds the problem. Operators facing a five-and-a-half-year average wait to renew consents, with nearly half of all plants due within a decade, are working against deteriorating assets. The 22 percent of plants already on expired consents are operating in a regulatory grey zone in the meantime.

The metropolitan-provincial divide is worth noting. Tertiary treatment at 99.6 percent in cities is a strong baseline, but those same networks carry nearly three times the blockage rate. Higher population density, older pipes and more connections all contribute. The report does not break down blockage causes, but the age profile of the infrastructure and pressure data from earlier Taumata Arowai reports are consistent with what the new pipe-condition numbers show.

Taumata Arowai built towards this dataset across three reporting cycles. Its data-collection framework was set in 2023, and updated drinking water rules published in August 2025 include performance measures for council-operated networks. The authority tracks estimated total water loss, consent compliance and a range of other metrics. A Statement of Intent covering 2022–2026 ties environmental performance measures to source water risk management.

For those working in local government water management, the report crystallises what has been an emerging picture across Taumata Arowai's publications. The authority now has a national dataset covering the bulk of the population. The numbers on overflows, pipe condition, leakage and consent status provide a baseline against which future annual reports will be measured. The political significance is that this dataset exists at all — the water reforms that created Taumata Arowai were contested, and the National-led government's decision to retain the regulator while dropping the Three Waters model means monitoring continues under a different delivery structure. The data-collection obligations on network operators remain.

What the report does not yet provide is trend data. As the third annual report and the first with comprehensive wastewater coverage, it establishes a starting point. Year-on-year comparisons on pipe condition, overflow frequency and consent compliance will become possible in subsequent reporting cycles. For now, the figures stand as a snapshot of a system under measurable stress.