The vast majority of Otago freshwater bodies could be swimmable in coming decades through an Otago Regional Council commitment.
Councillors decided at a committee meeting this week to set targets for 90% of lakes and 98% of rivers to be swimmable by 2030 and 95% of rivers and 100% of lakes by 2040.
However, this was a revision from a commitment councillors made in April to make 95% of rivers and 100% of lakes swimmable by 2030 and 100% of both by 2040.
Council chief executive Sarah Gardner said the targets were still "way ahead of anyone else’s" from a national perspective.
"Which is fine, but we have to realise we’re going to be really looked at in terms of the investment and how well we do."
Council senior policy analyst Rachel Brown said with the previous targets there was a risk of raising public expectations it was not able to meet.
Cr Michael Laws, who pushed for the higher goal, said the council should be more aspirational.
"I’m struggling to see why we wouldn’t still keep the targets."
The council should put more resources towards the project if it needed to, he said.
Cr Michael Deaker said the staff recommendations were aspirational, but achievable.
Cr Trevor Kempton said wanting 100% swimmability was "a bit nuts".
"I’m wondering if in their natural states this wasn’t achieved. Are we aspiring to something that’s never been achieved?"
The targets are under the National Policy Statement for Freshwater Management, through which swimability would need to be achieved at all flows.
A staff report said the region’s swimability levels were now at 82%, including 79% of rivers and 97% of lakes.
New targets could only be achieved with improving "poor effluent management" on some farms and stormwater and wastewater management in urban areas.
Land-use changes might be required in some areas.
It would probably take time and money and have "social and economic" implications for Otago residents, the report said.
