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Dr Brian Tuck shows off his near-pristine kettle – kept clean after installing the water de-ioniser pictured behind him.
The findings of a retired chemist may give hope to Warkworth residents who are up in arms about the quality of the town’s water supply.
Warkworth switched from sourcing water from the Mahurangi River to an underground aquifer in December 2018.
But soon afterwards, residents began to complain that the “harder water” containing more minerals such as sodium, calcium, magnesium, potassium, chloride and silica, were leaving deposits on appliances such as kettles, which was proving near impossible to remove.
Complaints boiled over at a Warkworth Area Liaison Group meeting last month, when attendees heard that residue build-up in plumbing fittings and appliances, such as hot water cylinders, dishwashers, washing machines, showers and coffee machines, will likely have to be ultimately replaced at enormous cost.
Summerset Falls resident Glyn Williams described the problem as another “leaky homes” crisis in the making.
He added that the harsh chemicals required to remove scale would inevitably end up polluting Mahurangi’s rivers and harbours.
One Warkworth manager Murray Chapman said the “hard water” was proving a major problem for local hospitality businesses. Cafés around town were having to spend thousands cleaning up their dishwashers, and a party hire company had had to employ extra staff to polish glasses. One motel owner had to reassure guests that their showers were not still dirty, despite staff having spent extra hours cleaning them.
Mr Chapman said One Warkworth planned a meeting with business owners to get a handle on the scale of the problem and would follow it up with a public meeting.
He suggested community groups join forces to make a case to Watercare that the town’s water supply needed to be cleaned up.
But after the meeting, Warkworth retired research chemist Dr Brian Tuck said he had gone a long way to solving the problem by installing a water de-ioniser (or water softener).
The de-ioniser removes two key elements – calcium and magnesium – that were causing deposits.
Dr Tuck had hoped that another troublesome element, silica, might emerge from the de-ioniser in the form sodium silicate, which is soluble in water and would be quickly washed away.
Unfortunately, the silica remains and continues to leave a deposit on shower screens and sinks when water evaporates. Nevertheless, the amount of remaining silica deposited appears to be minor.
Dr Tuck said silica bonds more easily to glass and porcelain when calcium and magnesium were present. When these elements were removed, the silica becomes less of a problem and was easier to clean off. More importantly, when calcium and magnesium were removed, calcium and magnesium carbonate scale was not deposited in kettles and other appliances when water was heated.
Dr Tuck began his quest to solve the water problem after noticing his kitchen sink and glass shower panes were permanently dirty following Warkworth’s switch to bore water.
Cleaning the sink required scrubbing with an abrasive chemical every week. Since the installation of the de-ioniser about a year ago, the sink and shower panes need no more than routine cleaning, deposits on the Tucks’ kettle were miniscule and, as far as he is aware, there have been no issues for his dishwasher or hot water cylinder.
Mr Tuck hit on the de-ioniser as a possible solution after securing an analysis of the water content from Watercare, which disclosed the level of calcium and magnesium in Warkworth’s water and persuaded him that dealing with these elements was the key to resolving the problem.
He secured a second-hand de-ioniser for $650 from Aqua Filter Rodney and faced the additional cost of a plumber to install the system.
Dr Tuck said the de-ioniser needs no electricity and requires little attention once installed.
Although installing a system represents a significant cost for a householder, Dr Tuck is sceptical that Watercare could be persuaded to treat the water itself, saying that the organisation’s responsibility only extended to supplying drinkable water.
He added that the cost for the industrial treatment of water closer to the source would be enormous, particularly if silica had to be removed.
“It’s a very energy-intensive process and with some of the methods used you would not want to drink the water afterwards,” he said.
Nevertheless, Dr Tuck’s claims have received a sceptical response from water softener supplier Aqua Filter Rodney.
Aqua Filter master & commander Steve Reynolds says Snells Beach water is high in silica but has no calcium and magnesium. Nevertheless, Snells Beach water is as bad as Warkworth’s for water spotting on glass.
“Having said that, Brian is using the softener and I am not, so maybe the silica is easier to clean off, but I don’t understand it from a physics point of view,” he says.
“I could not in a clear conscience sell an item and know it’s not going to work properly – customers are always left a little miffed, even when it’s explained to them that the item is not a perfect solution.”
Mr Reynolds said new water softeners range in price from $1600 to $2600. The cost of plumbing them in would be around $600 to $1000.
Watercare was also approached for comment on this story but had not done so by the time Mahurangi Matters went to press.
