The Havelock North rest home which suffered the only fatality linked to the town's gastro outbreak so far is suffering another wave of illness.
A sign out the front of the Mary Doyle rest home says it's closed as a result of an infectious bug.
Jean Sparksman, 89, died during the campylobacter outbreak. A post-mortem showed she had other underlying health problems.
Earlier on Tuesday, a Hastings primary school closed after a positive reading for E. coli in its water supply.
Haumoana School had increased the frequency of its water testing following the gastro outbreak in neighbouring Havelock North.
The school's water had been clear as recently as last week, but a test taken Monday was returned at 9:15am with a positive result.
Principal Jane Gallen says it could be a false positive, but the school was taking the precaution to close for the day.
"The Ministry of Education and Ministry of Health were immediately contacted to provide advice and support, and our board of trustees has recommended our school be closed today whilst our water is investigated," Ms Gallen wrote in a Facebook post.
The water will be retested, with the school hoping to get an answer for concerned parents by Wednesday morning.
"We will be working closely with health agencies and the Ministry of Education today to ensure that our drinking water supply is safe and school can be reopened as soon as possible."
Hastings District Council water services manager Brett Chapman says the school's water comes from a private bore and didn't think it was related to Havelock North's contamination.
However, the council is considering chlorinating the Haumoana, Te Awanga and Clive bores.
"We need to gather more information on that, but that's one possible action we could take."
The council is planning to treat the water with UV rays on Friday.
More than 4000 people in the Havelock North area have been affected by the campylobacter bug since it was first reported about two weeks ago. But there are now fewer cases, meaning the worst of the mass illness may be over.
But with that wave of illness abating, there is now some concern about cryptosporidium, also known as crypto, and giardia in the water.
However, acting Medical Officer of Health for the Hawke's Bay District Health Board Dr William Ranger says it isn't uncommon to find the bugs in water at this time of year.
"It's not a new occurrence that's happening here. Cryptosporidium and giardia occur throughout the community throughout the year so there's a background rate of these illnesses."
The council chlorinated the water following the contamination, but there was still a boil water notice in place because cryptosporidium is unaffected by chlorine.
"Because there was some event earlier in August which affected the water supply in Havelock North, we were concerned about a number of germs that could have got into the water supply at that timeâ€¦ that is why we issued the boil water notice at that time."
They symptoms of crypto and giardia are similar to campylobacter including vomiting and diarrhoea.
The Government has launched an independent inquiry into how and why the town's water supply was contaminated, and also the response of local and central government to it, amid criticism they were slow to act.