Almost 40 percent of water supplied in KwaZulu-Natal is being lost, Water Affairs Minister Edna Molewa revealed on Monday.
In a written reply to a parliamentary question, she said the 14 water service authorities (WSAs) in the province lost, in total, more than 22 million cubic metres of water each month in the past financial year.
This was out of the 55.5 million cubic metres of water that was pumped into KwaZulu-Natal's supply systems each month during the period 1 July 2011 to the end of April 2012.
Asked about the term "lost", department spokesperson Sputnik Ratau said this included pipe leakage and illegal abstraction, as well as water not billed for by the authority.
According to an annexure attached to Molewa's reply, the WSA with the highest loss was the Newcastle local municipality, which lost, on average about 70 percent of its input a month.
Of the 1.83 million cubic metres put into its water system each month, 1.28 million was lost.
The eThekwini metropolitan municipality, which includes the city of Durban, lost 9.39 million cubic metres of the 26.15 million cubic metres put into its system each month (35.9 percent).
Annualising the total of the monthly averages for all 14 of the WSAs gives a total loss for the year of about 266.4 million cubic metres. In comparison, the capacity of the province's Midmar Dam is 235 million cubic metres.
The water losses are also almost twice as large as the gross storage volume of the new Spring Grove Dam, which is being built on the Mooi River and expected to be completed next year.
Water authorities in the province are also looking to desalination of sea water to help augment supply in what they describe as a "very stressed" system.
The parliamentary question was posed by Democratic Alliance MP Gareth Morgan.