It has been two years since tragedy hit Havelock North, with 5500 people falling ill, and four people dying, due to contaminated water.
The crisis hit Havelock North in mid-August 2016, with a boil water notice being issued on August 12 when it was suspected that water contamination was the cause of an abnormally large number of people falling ill with gastro.
Two years on controversy remains around the subsequent decision to chlorinate water supplies in Hastings and Napier.
Guardian of the Aquifer spokeswoman Pauline Doyle said chlorinated water posed health risks and did not prevent all water-borne diseases.
"Chlorine is known to be harmful to human health and many residents are suffering in silence.
"Contrary to claims by council, chlorine does not provide protection from all water-borne diseases."
Guardians of the Aquifer were running a petition to hold a referendum at the next local body election on the chlorination issue.
"We've got a petition to the Government, calling for a referendum to be held at next year's local body elections, on the issue of mandatory chlorination.
"We want chlorine-free water in Napier."
They are aiming for 10,000 signatures, with about 1000 gathered so far.
That petition was running specifically in Napier although Doyle said she had heard from people interested in starting a similar petition in Hastings.
A Hastings District Council spokesperson said chlorination would remain for the time being.
"This situation will continue until such time as advised otherwise."
They said chlorination was one of the two government recommendations after the inquiry into the Havelock North contamination crisis.
"The first being that all drinking water supplies be treated at source.
"Secondly a requirement for residual disinfection [chlorination] of the water supply as it travels through the pipes to your taps.
"These recommendations came from the Director-General of Health to the chief executive of every drinking water supplier [councils] urging the immediate implementation of both recommendations."
Chlorination in Napier began in May 2017, after a spike in positive E.coli tests in the city's water.
Director of infrastructure services at NCC Jon Kingsford said NCC and the Hawke's Bay District Health Board deemed the presence of E.coli was too high a risk to keep water untreated.
"The Director-General of Health and the HBDHB have stated the risk to the public is too great if drinking water is left untreated.
"Until chlorination of Napier's water supply commenced, Napier only had a single barrier to contamination, this being the theoretical assumption of secure ground water.
"The inquiry made it clear that having only one barrier to contamination was no longer acceptable practice in New Zealand."
Napier City Council is looking to install two de-chlorinated water stations so the public would have the option of drinking de-chlorinated water.
Hastings District Council has three de-chlorinated public taps, one each in Hastings, Havelock North and Flaxmere.