Carterton residents are again being told they need to boil their water after another E coli reading in the town's supply.
Photo: AFP
This means boiling all water before being used for drinking, making baby formula, juice, ice, washing fruit and vegetables, other food preparation and cooking needs, or brushing teeth.
The previousl boil water notice which began on 12 March was only just lifted on 28 March.
The council was warning residents not to expect this to be lifted for at least seven days while a thorough investigation into the cause takes place, and remediation work can be carried out.
"Last week, the Council lifted its boil water notice after locating a potential faulty valve which resulted in a low-level E coli bacteria reading in its town supply," the Council said.
"Despite repairing the valve and increasing the flushing regime by 50 percent, the council received a low-level E coli reading in one of our sampling points in Fisher Place at around 1pm.
"The risk to the community is extremely low but the Council is taking a precautionary approach."
Water and waste experts Lutra are investigating alongside the council.
"The Council team have eliminated a number of potential contamination sources and have located and fixed two probable contamination sources," chief executive Jason Colton said.
"This latest positive result shows that there is least one other potential contamination source in the water supply network that needs to be located and rectified. This is proving challenging to locate."
Carterton's mayor Greg Lang said it was very frustrating and disappointing to once again issue a boil water notice.
"We were very confident, we'd had the experts in and we thought we had eliminated the cause in the network, but this reading confirms there is still something there."
Land said he realised it was an inconvenience, but it was important to boil water to keep each other safe.
Residents can get water from outside the Carterton Event Centre.