Havelock North residents have expressed their anger at a heated public meeting about the gastro outbreak on Tuesday night.
Locals demanded answers about what caused the water to become contaminated and the council's communication after it became aware of the outbreak.
A representative from Aged Concern said elderly people only found out about the contamination from people on the street, and a man in his 80s says he and his wife had diarrhoea for six days and no one visited except for a person trying to sell them a water cooler.
The Hawkes Bay District Health board has confirmed more than 5000 people were affected.
The investigation into how the water supply became contaminated is continuing.
Diva Bar and Bistro, a Havelock North pub, found out from its patrons that the tap water was contaminated after serving it all day.
"[There were] a couple of unhappy customers saying, 'You know it's contaminated, right?' and all of us just had to turn to each other and say, 'No we didn't know that'," says bartender Lewis Soden.
"We had no idea."
It was only the next morning council alerted them and they want to know why it took so long.
"It's just made things hard for the business, hard for the workers, and people don't feel safe to go out and have dinner," Mr Soden says.
It's one of the questions mayor Lawrence Yule faced at the public meeting which attracted around 500 people.
Mr Yule expected a number of them would be angry.
"But we said we'd front up and that's what we're doing tonight," he says.
But they're no closer to finding the cause.
"It's either got through the well somehow or it's in the groundwater," Mr Yule says.
A 2015 Hastings District Council report released to Newshub shows the Brookvale Road bore was prone to surface flooding, and in a bid to avoid contamination it had fitted additional alarms to stop the pumps during a flood.
It also said:
"Provision has been made to chlorinate water using a 13 percent sodium hypochlorite solution during an emergency contamination event."
But the council says this doesn't activate automatically, and Mr Yule says it doesn't look likely that surface flooding is the cause.
"There are alarms on the Brookvale Rd bores but one bore never had any water in the top of, it and the other one an alarm went off for a small period of time."
He says it appears something is still contaminating either the bore or the aquifer - even now.
"The contamination has been going on for nearly two weeks post that event, if something got in the top of the well it would have disappeared quite quickly," Mr Yule says.
The water in the area will be chlorinated for at least three months, which is another issue that put heat on the mayor on Tuesday night.