Firmin asked the Whanganui public to stand with what she said was iwi in opposition.
"This is not a Māori issue. This is an us issue, because it affects our environment," she said.
Horizons councillor Nicola Patrick said the Whanganui application would be dealt with by staff, not councillors, and their decision would be based on a set of rules.
That caused Retihia Cribb, among the crowd, to say those rules weren't her rules.
The Whanganui Groundwater Management Zone has 46 billion litres of water available for taking each year, the application says, and 62 per cent is taken.
Whanganui and the small towns around it are allowed to take up to 54 million litres of bore water a day. Some major irrigators in the Rangitīkei sand country use as much groundwater as a small town.
Across the Horizons region there are 8700 bores, and anyone taking more than 50,000 litres a day has to have consent.
The application by Aquifer 182 is for 750,000 litres of water a week - more than 100,000 litres a day. It intends to start with 150,000 litres a week, and build up. The water would be packaged in 20 litre-plus containers for hotels and restaurants, and in smaller glass bottles for retail.
It would be sold in New Zealand and overseas, as a liquid and frozen.
The bore it intends to use is 80m from the Whanganui River, and 237m deep. Taking from it would have no effect on the river or other surface water, the application says. It seeks a non-notified consent, with a term of 27 years.