The Bluewater Bar and a function centre could also close if water ran out.
"And we've got a huge Christmas party tonight there as well."
Hawke's Bay Chamber of Commerce chief executive Wayne Walford said water shortages were common and it was time the region had better infrastructure to help minimise the situation.
"One of the challenges we have in this region is that we always have a shortage of water at some stage over the summer, and that's why I was hoping Ruataniwha (water storage scheme) would help us to minimise. I just hope it doesn't impact local businesses, it will be really sad if it does.
"This region always suffers from water shortages in the summertime and it's something we should be doing better at, and we should have better infrastructure for and managing by now."
Rural and semi-rural businesses were not expected to be affected.
A Napier City Council spokeswoman said there were no commercial irrigators hooked up to our system.
"Napier is an urban area and the agricultural businesses we are aware of are our outside our water boundary."