The notice affected about 12,000 Rototuna properties, after the positive test for E. coli during routine testing.
The council said Sunday’s test results showed no E. coli at the Rototuna reservoir or any sites around the city.
The boil-water notice applied to the Rototuna Water Supply Zone, which covered about 29,000 residents, as well as a small number of Waikato District Council residents supplied from the zone.
It also applies to the Flagstaff area.
Only Waikato residents supplied by the Greenhill bulk supply point, being Gordonton and Puketaha, were impacted by the event, the Hamilton City Council said.
These residents were on the on-demand supply and the rural trickle-feed supply network and must also boil water for as long as the notice was in effect.
Three Waters director Maire Porter said it was encouraging that the latest water test samples were clear of E. coli.
She said people should still boil all tapwater and the notice would only lift after three consecutive days of clear tests.
A map showing the area affected by the boil-water notice. The impacted area includes Gordonton and Puketaha. Photo / Hamilton City Council
The water needed boiling before drinking, including making sachet juice or drinks, making ice, food preparation, brushing teeth and preparing infant or toddler formula.
“Washing hands and good hygiene is important, as E. coli can spread from person to person,” the council said.
“This is particularly important around more vulnerable members of the community, like infants, the elderly and people with immuno-compromised conditions.”
These groups and pregnant people should seek advice about drinking water from their healthcare providers, it said.
Electric jugs with a cut-off switch could be used as long as they were full, allowing the water to come to the boil and waiting for it to switch off, the notice said.
“Do not hold the switch down to increase the boiling time.
“Water can also be placed in a clean metal pan and brought to a rolling boil for one minute. Boiled water should be covered and allowed to cool in the same container.”
Porter said the council was still investigating the cause of Saturday’s positive test.
“An incident management team has been established, and we will be working closely with Taumata Arowai [the Water Services Authority] and the Ministry of Health on next steps.
Porter said the council’s website and social media channels will carry updates as investigations continue.
– RNZ