Hidden killers are lurking in Whanganui district water tanks, prompting a warning to keep tanks maintained and clean.

Bacteria such as E.coli, giardia and norovirus are proliferating in the warmer water, leaving mainly rural households vulnerable to illness during spring and summer.

Danny and Julie Perkins noticed soon after moving to their Turakina Valley property four years ago that the whole family was getting sick. "All five of us were sick," Mrs Perkins recalls, "we just couldn't shake it". Symptoms included vomiting and diarrhoea, and when they persisted for over two weeks, the Perkins started to suspect their water supply.

"There was no funny taste, and the water wasn't brown", says Mrs Perkins, "but we decided to start boiling the water to see if it made a difference".


The symptoms went away, and the family kept on boiling their drinking water - especially for the three children and visitors, who inevitably got sick if they drank the tap water. "It just became routine to boil the water," says Mrs Perkins. "I would always have several containers on my kitchen bench that I poured the boiled water into to let it cool, and we just used that for drinking and cooking."

Chad Meads, director of water filtration company Safe H2O explains, "The challenge with rural tanks is [that] over time, sediment from ash, dust, sprays, chemicals, animal and bird droppings, dead rodents, birds and vegetative matter forms a dense layer on the base of the tank."

"This sediment is a breeding ground and food source for potentially harmful bacteria that can make users of the water supply extremely unwell. "

The danger lies not only in drinking the water; even showering or washing your hands in contaminated water can be harmful. While healthy adults in their prime can build up certain immunity to the bacteria, children, the elderly, and those with a compromised immune system are especially at risk.

Richard and Anna Campbell opened a Safe H2O franchise in Whanganui in June this year. Mrs Perkins saw the before and after photos published on Facebook after the Campbells had cleaned out another local family's tank and thought "our water could never be as bad as that."

"I wondered how those people had let their tank get into such a state," she says.

The Perkins had considered having their tank cleaned out several times, but had always hesitated because of the cost of replacing the water. The system employed by Safe H2O uses a mobile filtration unit to purify and retain the existing water, which was the deciding factor for the Perkins. "We wouldn't have to pump thousands of litres of our untreated bore water back into our tanks, which would have cost us a lot in electricity and may have been contaminated anyway."

Mrs Perkins remembers looking on in shock as Richard Campbell siphoned out litre after litre of black water from their water tanks. "I couldn't believe it; I thought, 'what am I doing to my family?'"

After having their tanks cleaned, the family have gone back to drinking tap water, and have had no further symptoms. "Water has always been first choice in our house; I feel so much better knowing my children can safely drink the tap water now," says Mrs Perkins.

The Dalgleish family of Brunswick have a similar story to tell. "I can't say for sure it was the water," says Sharee Dalgleish, "but our kids kept getting tummy bugs, we all did."

"We've been at our place for 14 years, and we filter the water but had never actually had the tanks cleaned." she says, "So we thought that we had nothing to lose by trying it."

The Dalgleishes were some of Richard and Anna Campbell's first customers, and the job was completed one evening while the family had tea. "It was so quick and easy," Mrs Dalgleish says, "and while I haven't got any scientific evidence that the water was making us sick, we all feel better now."

"Our kids say that the water now tastes better, and they certainly drink more of it," she concludes.