He said that "something" was unknown so far, and may never be known. However, he said it was more likely to be a substance, than an object.
"Unfortunately we would need to know what to test for to find out what it was. We have asked NRC to follow-up on this to see if there is any evidence of anything in the water."
Late yesterday afternoon, Mr Weston said the water supply to residents hadn't been reduced because the water stored in the reservoirs and production from the Ahuroa plant supplies water into the area.
"However the reservoir levels are dropping, and therefore we have asked that people conserve water to maintain the supply."
Mr Weston said the clarifiers were being cleaned out and he hoped the plant would be operational between 7pm and 8pm.
Residents would still need to conserve water today, because it takes time for the reservoirs to completely re-fill. He said Wilsons Dam had been inspected and looked fine.
"The Ahuroa plant that takes water from the Ahuroa River is operating fine, however we are unable to increase production at this plant."
The council is asking residents in those areas to avoid unnecessary water use, including watering gardens and playing with water outside.