The Clutha District Council has applied to the Otago Regional Council for consent to continue discharging treated wastewater to Tuapeka Creek. The existing consent expires in December.
Council projects engineer Peter Ross said while this system worked well in some areas, it had not consistently met limits for dissolved oxygen, biological oxygen demand, suspended solids and faecal coliforms.
"Not only can this not continue, but council needs to consider options for meeting increasingly stringent conditions," he said.
Whatever is done, ratepayers can possibly expect to pay more than $200 each to fund the upgrades needed.
Mr Ross said a treatment upgrade was needed but the council had asked for a three-year period to consider the various options needed to comply with new standards and to build any new plants.
Investigations to date had identified a multi-stage second treatment pond as its favoured option, estimated to cost about $660,000 and any costs associated with buying property.
This was the cheapest option but would still cost Lawrence ratepayers an extra $238 to repay the loan needed to fund the works.
This would be on top of the existing sewage rate of $202.50.
For a medium-valued Lawrence property, these amounts would add 12% to this year's rates.
Submissions to the application close on September 26.
