Hamish McNeilly/Stuff An electronic sign at the entrance to Waikouaiti, near Dunedin, warns people not to drink the tap water there. As the council scrambled to find the source of the contamination, affected residents were offered blood tests. Water testing carried out by the Dunedin City Council since found no further readings over the maximum acceptable limit for lead. That has raised questions over the initial testing results, and this week the council was asked specifically if it could rule out whether the initial samples showed false positive results. Hamish McNeilly/Stuff “We are not yet able to comment as the investigation is ongoing,” a spokesman said.