The Hastings and Flaxmere water supply tested positive for contamination this morning, a council source has told ONE News.
Water is still being chlorinated in the area, as well as Havelock North.
Further tests will continue.
There has now been 476 confirmed and probable cases of campylobacter in the Hawke's Bay.
Health officials say there are now 10 people in hospital and none in intensive care.
Hawke's Bay DHB CEO Kevin Snee says people should now keep an eye out for any secondary complications caused by campylobacter - such as joint pain and tingling in hands and feet.
The number of people affected by the gastro bug remains at 4,100 but it's not known how many people who are now outside the region have also fallen ill.
Initial results remain inconclusive
Dr Snee says the results of yesterday’s DNA testing of the contaminated water were inconclusive - meaning authorities are no closer to getting answers to just how the water became contaminated.
The tests show bovine contamination, so most likely to be from sheep, cattle or deer.
But Hawke's Bay District Council CEO Ross McLeod says nothing can be ruled in or out at this stage and more testing will be done early next week.
There are two issues - where the contamination came from and how it got into what should have been a secure water supply.
Mr McLeod says the council will fully cooperate with the Government inquiry into the saga. Despite criticism from locals, he's defended the way the council has handled the water contamination crisis.
And he says if the council is found at fault, as CEO, he will take responsibility for that.
The council will also look at what can be done to support people who haven't been able to go to work due to their own illness or family illness.
No work has been done on how much the scandal has cost so far but Mr McLeod says the costs will be made public once known.
Havelock North residents are being told to continue to boil their water.
Health authorities are also warning people to keep up with hand washing and hygiene practices for the foreseeable future to stop the spread of any secondary infections.