About 2700 Selwyn properties were either never billed or undercharged for water, and the council has yet to decide whether residents will have to pay back the money, which could reach $2.9 million.

Selwyn Mayor Lydia Gliddon said the people affected were not to blame.

“It’s actually no fault of their own… and you know that’s our problem to solve.”

The council found its historic systems had not consistently captured every property receiving water services, and some properties were undercharged between July 2024 and December 2025.

The $2.9 million is an early draft estimate and is likely to change, because meters have not yet been checked property by property.

An independent report by PwC will go to the council’s finance and performance committee on 22 October, and Gliddon said it would give a firmer picture of what the failure meant for the district. That meeting will be closed to the public, but the council says it intends to release the report later.

The problems have come to light as water charges move off rates bills and on to quarterly bills from Selwyn Water, the council-owned company that took over drinking water and wastewater services on 1 July.

The fixed charge for drinking water and the wastewater charge have been removed from rates demands and now appear on the Selwyn Water bill, alongside the charge for water use.

Gliddon said the council recognised the change had caused pain and confusion.

“This is new for our district, and we recognise there’s a lot of pain and sometimes confusion around what are these charges on my bill that I’m getting.”

With a very strong El Niño expected to bring a dry, windy summer and higher wildfire risk to Canterbury, Gliddon urged residents to follow Fire and Emergency New Zealand’s social media page and attend its community events.

She went to one in Sheffield last week, where the biggest message was making sure fire trucks could get in and out of properties.

“That’s actually one of the hardest things for them, is making sure they can get trucks in and out.”

The council has also launched an interactive map showing which roads will be repaired, resealed or patched during this construction season, which runs until April.

Gliddon said the warmer weather was better for getting a good seal down, so the patch repairs seen over winter would now give way to full repairs.

“It’s great to be able to show the work that we are doing in the community, and for people to see what is going on around their neighbourhood too.”