Kaitaia Business Association chair Andrea Panther said the cost increase was of concern for cash-strapped ratepayers.
"We have a low percentage of people (around the district) who pay rates. Any time there is an increase in rates, it hurts," she said, although the increase was a "necessary evil" to ensure business could continue during droughts and to allow for future growth.
The June monitoring report said the council had allocated $11.3 million to the project in its long-term plan versus the now updated $16.7 million price tag. The council would look at how to fund the project through its next long-term planning process if support was not received from the PGF.
The Sweetwater bore project dates back almost a decade, on land offered to the council after the 2010 drought. The council has had a consent to take the required water since 2012.
The scheme will pipe water across private land to Kaitaia, the aim being to build three months' resilience into the town's drinking water supply by providing 100 days of water at a rate that is roughly double current daily use, to potentially provide a reticulated supply for Awanui and to cater for future development.
The project involves sinking two deep bores, building a site access road, on-site infrastructure to pump, store and process the water, and extra receiving infrastructure at the treatment plant in Kaitaia. Land will be bought at the bore site. Water will be pumped 14.2km. The PGF application said six property easements were needed, to be negotiated under the Public Works Act.
The council recently said negotiations with affected land owners were "well under way," and compulsory acquisition was unlikely. Easement land valuations were part of those negotiations.
The application also said detailed design work was scheduled to start in April, followed by buying labour and resources in July and construction at the end of October.
Earlier this year the council undertook to have water flowing before the end of autumn 2021.