 We all enjoy living in the modern and clean cities of today. Public health is protected largely by the underground infrastructure that forms a sophisticated sewer network. Sewer pipes are built in tender to last for a century or longer, but with time and urban growth come problems like corrosion. This costs governments billions of dollars each year, with some sewer pipes collapsing in just 10 to 20 years. Researchers at Australia's Advanced Water Management Centre at the University of Queensland have been studying these problems as part of a program called SCORE. Sewer corrosion is due to the microbial production of hydrogen sulfide. This is caused from sulfate in sewage. The water industry has been trying to minimise corrosion by removing hydrogen sulfide after it's formed, yet the high levels of sulfate creating the problem continue to be overlooked. So where does the sulfate in sewage come from? In a paper published in Science Journal, UQ researchers answered this question looking at a typical urban water cycle. A dam supplies the drinking water treatment plant with source water that may already contain some sulfate. More is added during coagulation, an essential process to clarify the water by removing suspended solids through the addition of coagulants like aluminium sulfate. When it reaches a household, liquid waste discharged by the users continues to increase sulfate levels in the sewage. Surprisingly, the aluminium sulfate added in drinking water treatment contributes substantially to the sulfate levels, so if we change the coagulant we can reduce the sulfate concentration and subsequent sewer corrosion. It's even possible to remove the sulfate from the source water using desalination. Protecting sewer pipes can be best achieved by optimising right from the source. Often this is not happening because different elements of the urban water system are managed separately. This study shows the major benefits that can be achieved with integrated urban water management if collaboration happens between all entities involved.