"They were asking us what they should do in events like this and it was definitely a wake-up call for many."
Sutto manager Graeme Smith said it would confirm his "worst nightmare" if the Hastings supply was contaminated.
"If anything it has certainly taught us to up our game on the hygiene front," he said.
Mr Smith said they were already boiling any water they used for food and drinks and were only selling bottled water to try to reduce the risk.
Jonathon Dick and Hamahona Ambler enjoyed a cup of coffee at the cafe yesterday morning and said the news had definitely made them think twice.
"I think it makes you paranoid not knowing what water is currently safe," Mr Dick said.
They both agreed that it would affect their decision to eat and drink in town and hoped the issue would be resolved soon with the local businesses hit badly.
"I know for us we are having to push everything out two weeks, as most of our staff are down either with the bug or looking after families," Mr Ambler said.
Mrs McDade said a lot of businesses in Hastings were run by Havelock North residents, particularly the accountant and law firms.
Read more:
• Hastings water chlorinated today
• E-coli indicator found in water tanker
• Ministry blamed for risk to water
"Companies had a quiet week with a lower number of customers and also staff."
BJ's Bakery manager Paytra Brown was concerned by the news but said so far the business was coping.
They were notified about the water at 10.45am yesterday and since then had stopped serving tap water. "We put a copy of the email we received by the counter advising our customers of the current situation," she said.
Hastings resident Rosie Bourke had been avoiding Havelock North and said with the new information she was tempted to stay at home.
"It is really scary and I would definitely be wanting to stay away from restaurants and cafes," she said.
The council said the Hastings and Flaxmere water supply was chlorinated yesterday as part of a precautionary approach.