Leaving Christchurch's water untreated is a "high-risk strategy" that could lead to tens of thousands of people quickly becoming sick, the Havelock North water investigation has been told.
However, one Christchurch City councillor says chlorinating the supply would be "insanity".
Campylobacter contaminated a bore supplying Havelock North's drinking water in August, leaving about 5000 people, roughly a third of the Hawke's Bay town's population, infected and sick.
Deborah Berlin spent seven days battling the ravages of the disease while trying to care for her newborn baby and two young children.
"You've got extreme fatigue, you can't keep anything down, you've got no energy and no ability actually to function but obviously you just have to.
"The kids got really really bad headaches and I don't think the children had really experienced headaches before so I think that was a really horrible thing for them. And cleaning up after someone else when you're not feeling well is probably like torture."
It was the country's worst ever outbreak of waterborne illness. Some 45 people became so sick they went into hospital and the illness may also have contributed to three deaths.
It is something the head of industry group Water New Zealand, John Pfahlert, is keen to avoid happening again in the 20 percent of regions that continue to supply untreated drinking water. See more