Stormwater identified as neglected water

Latest findings by Water New Zealand have revealed significant under investment and a lack of consistency at a national level for funding stormwater networks across Aotearoa New Zealand.

The latest National Performance Review has found that investment in stormwater networks has not been sufficient to cover asset depreciation.

Capital expenditure on renewing or replacing stormwater assets by councils covered in the review has been, on average, less than 70 percent of the depreciation over the past five years.

The review’s author, Water New Zealand insights and sustainability advisor, Lesley Smith says this means we can expect our stormwater infrastructure and services to decline.

She says expenditure was roughly a third of that spent on water supply and wastewater networks across participants in the 2021/22 year – 36 percent and 33 percent respectively.

“Aucklanders spent $186 million on stormwater networks. Outside of Auckland, regions covered in the review invested only $283 million, compared with $782 million on drinking water and $850 million on wastewater.”

Water networks play a critical role in managing urban run-off and preventing flooding risks.

She says in light of recent flooding, the current piecemeal approach for funding stormwater networks requires urgent attention.

“Revenue for funding stormwater is raised through council rates and the exact rating mechanism varies across the country.

“We identified seven different rating approaches. One council stated it did not have a rating mechanism for stormwater while several others were not able to clearly distinguish what proportion of rates collected was allocated to stormwater.

“For councils who could ring fence stormwater related charges the annual amount collected per household in 2021/22 varied more than ten-fold across the country, from $33.54 to $409.12."

The National Performance Review has been undertaken by Water New Zealand since 2008. It provides an annual performance comparison of drinking water, wastewater and stormwater service provision in New Zealand based on voluntarily supplied information from water utilities. This current NPR covers information provided by just over half of the country’s districts - 33 of New Zealand’s 64 drinking water, wastewater, and stormwater service providers.