An early water meter trial in Marlborough found one house in Havelock leaking 30,000 litres a week. New results show two houses leaking that a day.
Properties in Havelock and Renwick will, from July next year, start paying for how much water they use, but the trials and test runs to get the scheme over the line continue to throw up eye-watering results.
One property in Havelock has been found using 33,000 litres of water a day, while another is going through 28,000 litres of water a day.
The test results from Renwick showed a house leaking 67,200 litres of water a day.
The council had installed meters at least 10 months before residents would be charged under the new system, so they had a chance to track their water use.
Residents were posted their first information sheet on their water consumption at the beginning of October.
A council spokesperson said the source of Havelock's two worst leaks had been found and were being patched up.
The council notified owners "as a courtesy" when there was evidence of a significant leak, but it was up to property owners to find and repair them, she said. Some of the 62 properties with leaks were zoned commercial.
"If owners are concerned they may have a leak they can check for the presence of a leak flag on the meter screen and by conducting a leak check to determine the size," the spokesperson said.
The meters were mooted as far back as 2016, with trials carried out in 2017 and 2018, as the council tried to find a solution for the towns' ongoing water problems.
Renwick dealt with water restrictions most summers and salt water could get into Havelock's water if demand jumped and water supplies dropped, as it had three years ago.
Climate change was expected to put more pressure on the aquifer which supplied its water. A sea level rise could see salt entering Havelock's water more often, and higher temperatures could encourage higher water use.
In the early meter trials, a house in Havelock was found to be using up to 30,000 litres of water a week. That property was not one of the two latest water wasters.
More meter information would be provided in future to provide a comparison between winter and summer use.
Under the new system, residents on water meters could be charged a flat fee of $200 for their first 200 cubic metres of water (200,000 litres). After that, Havelock residents could be charged $1.60 per 1000 litres used.
Final figures would be set at the long-term plan review.
Properties with "large" leaks of more than 72 litres a day would therefore use at least 92 percent of their base water allocation if they continued without fixing the leak.
Havelock residents paid an annual $510 fee at present.
The council agreed in April to keep shouldering water rates for 82 of the region's ratepayers when water meters were rolled out in Havelock and Renwick next year, to recognise situations where a landowner provided care or support to aged parents or children with special needs.
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