Federated Farmers raised the spectre of major changes to how local councils deal with wastewater in a letter to Otago political leaders last week.
It called for urgent transparency around the Otago Regional Council's land and water plan, due to be ready for notification at the end of October.
"We are asking the Otago Regional Council, and the region's district and city councils, to be transparent with local ratepayers and the wider community about the estimated costs of giving effect to Te Mana o te Wai under the land and water plan."
Federated Farmers raised concerns about incoming rules that would prevent water drawn from one catchment mixing with water from another catchment.
The group understood the regional council had also reached a "view that no wastewater that has passed through a human body, even once treated to a high standard, can be discharged back into local waterways".
Clutha District Mayor Bryan Cadogan said his council had conducted "high-level" investigations into the possibility of buying land, such as a dairy farm, to address that possibility.
"We have done the initial studies on the cost of discharge to land and discharge to water and there's not too much in between them.
"Don"t worry, it would still be unaffordable costs — ghastly — but the difference between the higher standard to discharge to water and the need to buy land for discharge-to-land means that at the end of the day it's down to semantics."
Regardless of where treated wastewater was discharged, Three Waters spending would make the council insolvent after 10 years.
The district"s 18,900 residents, over the next 10 years, were looking at $611 million in capital and operating spending on Three Waters.
"That"s $61m every year for the next 10 years. And people say we haven't been transparent?
"We have screamed out that that's going to happen."
Other mayors, to whom the letter was addressed, declined to comment.
ORC chairwoman Cr Gretchen Robertson said every Otago participant in the council"s land and water plan process identified good water as a priority.
"The plan creates regulatory pathways to these visions over time through rules and policies."
Still, the notion that treated wastewater could be required to be discharged to land appears to have raised concerns for at least one ORC councillor.
In emails obtained by the Otago Daily Times, Cr Michael Laws asked ORC chief executive Richard Saunders whether the forthcoming land and water plan required treated wastewater not to be discharged to any freshwater body.
"No," Mr Saunders said yesterday.
"The draft plan sets out a preference for discharge to land but there is not a prohibition on treated discharges to water.
"The draft also requires a higher bar for new systems, and progressive improvement of existing systems [upon reconsenting].
"Unfortunately the letter released by Federated Farmers contained a number of statements which did not reflect the content of the plan.
"I have met with representatives to discuss this yesterday and we will continue to stay in touch with them."
Upon receipt of the letter last week, the ODT asked the council whether its claims about costs and implications were accurate.
No clear answer was given.
Yesterday, Otago Federated Farmers president Luke Kane said it stood by the statements in the letter.
"It"s simply not good enough to say there are ‘some inaccuracies' without providing any details of what those inaccuracies are — they need to front up with the proposed costs and implications."
The group was asking "some very fair questions ... that deserve fair answers".
Central government had already extended the timeframes for the plan and there was "no need to rush this through by October", he said.
