Failure by the relevant authorities to properly treat drinking water supplied to Delmas residents might have triggered the recent outbreak of diarrhoea in the Mpumalanga town.
Tests by the department of water affairs have shown "insufficient levels" of chlorine were added to the water supply between September 11 and October 14, members of parliament's water affairs portfolio committee heard yesterday.
This resulted in a "pulse" of contaminated water - with not enough chlorine in it to kill harmful organisms - being piped to residents, the department's water quality unit head, Leonardo Manus, told MPs.
"There was a period when [chlorine] levels were fluctuating and unacceptable," he said.
Water affairs had informed the municipality by letter of the situation at the time.
The latest outbreak of diarrhoea in the Delmas area, the second since its municipality assumed responsibility for water services in 2003, has affected over 1000 people.
Water to the town, which consumes 160 megalitres a day, comes from 10 boreholes and a Rand Water pipeline.
Manus said though too-low chlorine dosing was probably the "trigger" for the recent outbreak, it was not a sufficient explanation for the problem persisting.
"Something else must be causing it," Magnus said.
The problem might be the result of mixing chlorine-treated water from the boreholes with that from the Rand Water pipeline, which was treated with a different chemical - ammonia chloramine.
"When you mix the two, you create new chlorine demand," Manus said, implying chlorine levels could again be too low.
But before any official conclusion could be reached, the records would need to be studied "to determine what role this played in the outbreak".
Manus noted that the three major outbreaks of diarrhoea in the town - in 1993, 2005 and this year - appeared to follow the onset of heavy rains in the region.
After the 2005 outbreak, it was recommended the town be connected to Rand Water by way of a new pipeline.
Manus said this process remained dormant because of a lack of funds, though he expected the project to be completed next year.
South African Municipal Workers' Union national research officer Jeff Rudin - who was granted permission to address the committee meeting by chairman Connie September - questioned government's priorities when it came to supplying safe drinking water.
The reason for the new pipeline not being built was a R78million funding shortfall, yet the country had allocated R20billion to build soccer World Cup stadiums, he said.
The problems with drinking water in South Africa was not confined to one town.
"We're sitting on hundreds of Delmases," Rudin warned, noting research showed it was becoming unsafe to drink water in many parts of the country. - Sapa