They have claimed the stormwater originates from the Northlake development, flows through the neighbouring Hikuwai development and the Department of Conservation's Hikuwai Reserve, before dropping down into the river.
During steady rain on Thursday another plume of brown sediment spreading into the Clutha River was captured on video by nearby resident Anna Simmonds.
She told the ODT it was the third time she had witnessed sediment being washed into the river, although it was not as bad this time as during the last event, in October.
She was concerned regulatory authorities appeared not to be acting and had complained to the ORC and the Queenstown Lakes District Council (QLDC).
Mr King said the latest incident was investigated and information was being collated.
The QLDC was responsible for subdivision control, but the ORC had been working with it to ensure "appropriate mitigation measures" were in place, Mr King said.
QLDC principal monitoring and enforcement officer Anthony Hall told the Central Otago News last month Northlake developers were "continually making changes and improvements to their site management plans" and that there had been an improvement in discharges in Wanaka generally as a result of the council working closely with developers.
mark.price@odt.co.nz