How could your down pipes be connected to the sewer?
Because some people don't understand that there are two systems of drainage - sewer and storm water - they can unwittingly direct the flow from their down pipes to the nearest drain on the property. Commonly, this is a drain that leads to a sewer. A large problem is caused by draining excess yard or swimming pool water in the same manner. All of these practices are illegal, and Council can prosecute if required, to stop them.