South Africa – Poor performance of household water filters
Tapping into the water filter scam, May 30 2009
Shocking new findings on water purification systems released this week have sounded alarm bells for owners of home filters.
Test results of samples taken from more than 100 homes in the Durban area revealed that:
— More than half did not meet the SA national standards for drinking water;
— The number of normal live organisms in the water was four times higher than in normal tap water; and
— The filters’ decrease or removal of chlorine had increased the growth of bacteria.
The voluntary tests were undertaken by eThekwini Municipality’s water department in the last few months. Samples were taken from a variety of table-top and under-counter home purifiers, which included most of the country’s leading brands. Domestic water filters range in price from about R950 up to R6500.
Neil Macleod, head of the city’s water and sanitation department, said many of the samples were also not on par with international standards for drinking water.
Macleod said the filter’s removal or reduction of chlorine in ordinary tap water left it unprotected and provided “a breeding ground” for bacteria.
Water purification companies, meanwhile, blamed the poor results on dirty filters, lack of maintenance and cross-contamination of the filter spout.
Macleod said the acceptable limit for normal live organisms in drinking water was 100 cfu/ml (colony-forming units per millilitre).
“We found 310 cfu/ml in some samples. The average was 170 cfu/ml in filtered water compared to an average of just 0.43 cfu/ml in unfiltered water,” said Macleod.
“It shows this water is not protected and organisms are growing at a hell of a rate.”
One sample, from a home in Durban North, revealed an organism level of just 1 cfu/ml in the family’s normal tap water, compared to a staggering 120 cfu/ml in its filtered water. “This family is literally making bacteria in their tap,” said Macleod.
He said the quality of the city’s tap water was within the South African standard, which is in line with the World Health Organisation’s standards. If home purifiers were used, he said, it was vital that filters were changed regularly and that filtered water was drunk immediately or kept refrigerated to stop bacterial growth.
Rand Water quality expert Karl Lubout said filters did not improve the quality of tap water. The results revealed very little change in the mineral content, he said.
“There is no advantage to the consumer, certainly not for those who live in metropolitan areas.”
Independent water expert Carin Bosman said the findings confirmed the general opinion of the use of home filters.
“If filters are not regularly replaced, the bacteria in the filters can end up in the water, known as bacterial ‘break-through’.”
Alessandro de Grandis, spokesman for H2O International, one of the country’s leading home water purifier suppliers, said regular maintenance and service of all water purification systems was vital. He said the kitchen had the highest chances of bacterial contamination in the home, which could lead to cross-contamination of the filter spout.
“So even if a water purification system is working correctly, this type of easily occurring scenario could introduce enough bacteria to show excessive levels of bacteria in an analytical report,” said De Grandis.