Havelock North residents say Hastings District Council knew the town's water supply was contaminated hours before they told people to stop drinking it.
Cassandra Heke said she was angry she heard about the contaminated water from her friends before the council made the issue public.
"The council knew about it on Friday morning but didn't tell anyone."
She had chosen to keep her child home for the day, but had called in for some voluntary work at Havelock North Primary School. "I think it's dreadful, especially the elderly, it's hurt the community."
She commended the school's ability to communicate with them as parents and update them as the saga worsened.
"It's just had a domino effect," she said, one of her friends may need surgery as a result of the outbreak, and many of her other friends and their children had fallen violently ill.
Hundreds of people have fallen ill after water became contaminated on Friday. The outbreak has been linked to an underground bore which tested positive for E. coli.
Hastings District Council was unable to be reached for comment this morning.
Colleen Pascoe had just done the school run for her grandchildren while their mother lay sick at home.
"It's disgusting the council didn't tell us."
She said her daughter, not knowing the sickness was waterborne, had focussed on keeping her fluids up drinking lots of water. Catherine Wedd, who had just dropped her child off at school, said she was angry about the lack of communication.
Her husband had gone fishing and filled bottles of water to take out with him, had he known about the contaminated water he would have taken store bought instead.
"I particularly just can't believe how bad the communication has been."
She said there needed to be an investigation into why people were not told sooner about the issue.
"We found out from the school before anyone else."
School children trickled into Havelock North Primary School at half the rate of a usual Monday morning. School road patrol did not go ahead with only one person from the team there to do the job.
One parent dropping his child to school saw the lighter side of things, saying, "I'm feeling a bit thinner today".
But he was just one out of many who were outraged the council's communication had fallen down at such a crucial time.
Tazmin Drawe said her family had not been affected by the bug because they never drink the town's supply of water.
They prefer to fill bottles from an aquifer available to the public, a place many could be seen lining up today as people are still unable to drink from their home taps unless the water is boiled.