ORC resource management director Selva Selvarajah said the regional council wants to ensure skifields are monitoring sewage treatment schemes and, where necessary, upgrade outdated wastewater systems to ensure they will have the capacity to deal with projected visitor growth.
A report tabled at a recent ORC meeting outlined how skifield wastewater systems were generally operating adequately around the Southern Lakes.
"The exception to this is the treatment system at Treble Cone, where effluent quality results fall outside the consented limits," the report said.
De Selvarajah said the Wanaka skifield needed to improve the quality of its monitoring systems.
"In our opinion, they are on the right pathway in terms of installing a good system. We would expect some teething problems during the commissioning process, but we are past that now.
"They have got to make sure they comply with consent conditions."
Treble Cone general manager Jackie van der Voort said the skifield was conducting an internal review with the assistance of the regional council and had completed a "significant investment" in its wastewater scheme about two years ago.
She admitted some internal reporting requirements and "administration" of the scheme had been "weak", but these would be rectified for the start of winter.
"We are confident it won't be an issue and it will be fully compliant for this operating season," Ms van der Voort said.
Dr Selvarajah said quality standards were not being met at a point where treated effluent was discharged via a "very, very, long drip line into the soil" on the mountain.
There was no evidence of the treated effluent contaminating mountain waterways or streams "at this stage", and while ORC staff were working with the skifield to monitor and improve standards, if this did not happen, legal action remained a possibility, he said.
A critical factor in deciding whether any enforcement action was taken was "how much commitment and work the company will put in to improving their standards", Dr Selvarajah said.
The ORC stepped up its monitoring of skifield wastewater schemes in response to a norovirus outbreak scare at Cardrona Alpine Resort in 2006, Dr Selvarajah said.
The skifield closed its operations when a virulent stomach bug swept through the alpine resort and laid staff and patrons low with vomiting and diarrhoea.
Cardrona Alpine Resort is also conducting an internal review ahead of the June start to the ski season.
Cardrona was forced to close down operations - for a second time in four years - when an oxidation pond came close to spilling over last year.
It closed for four days and brought in a rolling convoy of six trucks to drain wastewater from its oxidation pond and haul it to a disposal facility in Queenstown.
Cardrona operations manager Gary Husband said a consultant has been engaged to report on the system and an "appropriate course of action" would be taken in response to the findings, he said.
Despite the closures, Cardrona had not breached its resource consent conditions.
"We've operated well within our compliance conditions and we have every intention to keep doing so," Mr Husband said.
Meanwhile, Coronet Peak has "virtually finished" installing a wastewater treatment system near Queenstown, Skifield manager Hamish McCrostie said the new system would be commissioned in the next three weeks.
The upgrades would meet higher disposal standards and future-proof the skifield's infrastructure to meet a continued growth in estimated visitor forecasts, he said.
Coronet Peak was spending "hundreds of thousands" of dollars to handle sewage and wastewater.
