Liz Harris owns more than 100 Christchurch properties and has had to replace 22 hot water cylinders since chlorine was introduced.

A landlord facing a $40,000 bill for chlorine-damaged hot water cylinders says the city council should shoulder some of the costs.

Liz Harris, who owns more than 100 rental properties in Christchurch, has replaced 22 hot water cylinders since chlorine was introduced to the city's drinking water. She fears more are to come.

Before the Christchurch City Council started to chlorinate the city's water supply earlier this year, she had "never lost one [hot water cylinder] except in the earthquakes".

SUPPLIED Christchurch landlord Liz Harris has replaced about 22 hot water cylinders since June.

"I think they've got to take some responsibility and reimburse us, or at least a portion of it," she said.

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More than 2000 cylinders have been replaced across the city since June.

The findings of a recent investigation by University of Canterbury Professor Milo Kral found chlorine was most likely responsible for the spike in replacements.

The council said it agreed with Kral's findings, but would not reimburse property owners for the repair or replacement of damaged cylinders.

Water supply improvement programme manager Helen Beaumont said last week "multiple factors" could contribute to water cylinders failing, including "the quality and thickness of copper used".

Cylinder manufacturers, concerned they were being blamed for the failing cylinders, met with the council on Friday last week.

At the meeting was Trevor Edwards, managing director at Superheat in Woolston, who commissioned the study after a huge increase in demand for cylinders.

He said there was no chance the issue was with cylinder quality.

The auditing and certification process meant the copper thickness and quality of hot water cylinders had to be perfect for them to pass, he said.

Beaumont said the council agreed to change the wording of its response to the question of why cylinders were failing on the frequently asked questions section of its website.

It removed the words "quality and thickness of copper used", and instead said "the particulars of the installation" could be to blame.

Master Plumbers chief executive Greg Wallace said it sounded like the council was shifting the blame for cylinder failures to the workmanship of plumbers.

"To try and blame the installation when they've been working perfectly fine for 30 to 40 years just does not stack up," he said.

"I think the council here are trying to defer attention around the cost that Christchurch consumers are being hit with."

Beaumont said the council was not singling out plumbers, and was "not trying to attribute blame to any one factor".

Mayor Lianne Dalziel said last month the council may have taken a different stance on water chlorination had it been aware of the risks earlier.

An independent review commissioned by the council and released last month revealed its three waters team had become aware of the risks around chlorinating Christchurch's water supply as early as May last year.

These risks were not revealed to other council members until December.

Edwards was unhappy with the council's response and wanted it to recognise water chlorination as the sole cause of cylinder corrosion instead of just a contributing factor.

Harris said insurance was unlikely to cover the kind of gradual damage chlorine caused her cylinders.

The Insurance Council of New Zealand confirmed this was often the case when objects were corroded over a gradual period of time.

Good Girls Property Management's managing director Pru Morrall said 30 cylinders at properties she manages had to be replaced.

The damage would cost the landlords about $60,000 to fix.

Morrall said she quickly suspected chlorine was to blame when the water cylinders started failing.

"Within about 10 weeks it began, and it hasn't let up."

Kral said the next step was to track data regarding the specifics of hot water cylinder failures in more detail.

"We need site-specific detail, such as water temperature and water chemistry, over a wide range of sites within areas experiencing high failure rates."

The data could be analysed to help reduce failure rate in the future, he said.