The Gore District Council said in a statement yesterday testing showed nitrate levels had decreased across the network.
Gore District Mayor Ben Bell said the water supply was back within the allowable limits for nitrate, but the "do not consume" notice could not be lifted until three consecutive days of clear tests.
The council’s Three Waters team was flushing the system "to help run that dirty water out".
Mr Bell asked residents to check in on their neighbours as the situation persisted.
"Thank you so much for looking out for each other during this tough time."
An alert was put out on Friday night after elevated nitrate levels were detected in the water supply.
Residents were warned not to drink or use tap water.
Residents were advised boiling water did not make it safe for consumption and five water tankers were set up around town for residents to use.
Today, the council will conduct a further test — if it is below the allowable limits, it will mean the water is safe to drink again.
A fail will start the three-day process over again.
Environment Southland is investigating the issue, and Mr Bell said the district council had been hard at work to fix it.
"An event like this, it’s always easy to do better, but staff, especially the Three Waters staff, have done a fantastic job to help sort the problem."
Schools will still be open, with two tankers moving from their locations to close to St Peters and the Broughton St camping ground for easier access for staff and students.
Mr Bell suggested parents send their children along to school with drink bottles ready, as water fountains would not be able to be used today.
Reports of frustrated locals were noted, but he said it was a difficult time for everyone and council workers were doing the best they could.
"I think with any situation, people are frustrated and rightly so. They expect clean water.
"There was a bit of adversity to some of our staff, but it got a lot better once messaging went out,"
The tanker situation also led to some issues, as people lined up only to find the tanker empty, but Mr Bell said it was remedied through quick refills.
The next update is expected tonight.
