John Buchanan has been a plumber in Wanganui for 62 years and he's asking the question: Have Wanganui ratepayers been conned with soft water?

He's also asking who has soft water around Wanganui?

Mr Buchanan believes that people think they have soft water because they've been told by the Wanganui District Council (WDC) they have it.

Furthermore, he says, he has been approached by people who are "pissed off".


"They don't know enough and are unsure about what to ask and what they're being told about soft water. I feel for the old people who are asking, where is their soft water?"

He is also dubious of softened water because a lot of it is used to flush toilets, water gardens, wash cars or used in industry.

According to the council, water hardness varies across the city. But if the council has found supplies of soft water why is there a need to build a $1.2 million water treatment plant, he wants to know.

Mark Hughes, WDC infrastructure manager, said the amount of softer water provided by the additional bores was not enough to achieve the desired target soft water level. "The soft water plant provides further softer water to the mix into the overall supply," he said.

Council numbers show slight readings of softness in Wanganui East, Bastia Hill, Durie Hill and the rest of the city. Aramoho remains the same with a soft water reading of 50mg/l since soft water came onstream in July last year.

Mr Hughes said it was not an absolute measure but "council is reducing the water hardness".

Wanganui residents were told there would be a three-month commissioning process before they "noticed the change in water softness" and that they could expect "annual savings of $200 or more a year".

However, the WDC says it does not hold any information about such savings.


Mr Buchanan had been told that two towns in Australia had attempted to soften their water but it was "far too expensive".

He said the city's water softening scheme was an "utter waste of time and money and it should never have got off the ground".

In April, Mayor Annette Main said the council's focus was on securing Wanganui's water supply for the future and that soft water was part of that.

Ms Main said at the time that the council started looking for additional water sources because of the high risk of the existing sources at Kai Iwi. And while looking for more volume, it decided to look for softer water.

"The more water we could find that was naturally soft, the less money we had to put into a softening plant."


Chemical and electricity cost of running the softening plant - about $110,000 annually

The cost of drilling and commissioning bores for security of supply and finding soft water - $6.1 million

Cost of softening plant - $1.2 million

There is no separate levy charge for soft water and any costs after 2007/08 have been rated via the usual water supply charge

The Aramoho/Brunswick bore cost $600,000 and the balance was for the treatment plant that was commissioned in 2003 - total cost $2.5 million

Aramoho bore and treatment plant provides 3 million litres a day to Aramoho and parts of Wanganui East. This is a single supply and not mixed

Wanganui's average water consumption is 24,000 cubic metres a day

The softening plant capacity is 2600 cubic metres per day which is added to the main supply and, according to the council, makes enough difference to soften the water


Contains large amounts of calcium and magnesium - two minerals that cause soapy scum on glasses and lime residue on sink fixtures

WDC measures unit of hardness in milligrams/litre (mg/l). Water with a hardness of less than 100 mg/l is considered to be soft

Canada Mortgage and Housing Corp (CMHC): soft, below 17mg/l or ppm (0-1gpg). On that basis Aramoho at 50mg/l is slightly hard; Wanganui East, Bastia Hill and Durie Hill (at 90-100mg/l) are moderately hard. The rest of the city (at 140-160mg/l) is "hard" according to the CMHC scale.