More than 90 litres of water for every Perth household was lost from the Water Corporation's pipes.
The National Water Commission noted in its annual comparison of water providers that the corporation had the second highest rate for major utilities of "real water losses" (the difference between water produced and what passes through customers' meters).
Overall, real water losses for the corporation amounted to 21.6 billion litres in 2011-12 - the equivalent of almost half the Kwinana desalination plant's annual production.
Radio 6PR Perth looked to WaterGroup's Director of Water Loss Management, Ian Maggs to discuss the issues.
