With La Nina conditions predicted to continue into summer, MidCoast Council is calling on homeowners to help reduce the volume of stormwater getting into the sewerage system.
Keeping stormwater out of the sewer has long been a challenge, but persistent rainfall over the past two years has highlighted the extent of the issue across the MidCoast, with Council's sewerage system struggling to cope with the amount of water getting in from private properties.
Council's Executive Manager of Water and Systems, Marnie Coates, said the sewerage system wasn't designed to handle large volumes of stormwater.
"The sewerage system is designed to transfer wastewater from people's toilets, sinks and drains to the nearest sewage treatment plant. If too much stormwater gets in – which is what we've been seeing – it can overload the system and cause wastewater to spill out into places it shouldn't, like waterways, streets and people's backyards," said Ms Coates.
"That obviously poses some serious health and environmental risks, and requires expensive and unpleasant clean-ups."
Ms Coates said it also added to the cost of Council's services, as more needed to be spent on treating the excess water.
"All water that comes into our sewage treatment plants is treated, whether it's wastewater or stormwater, and that process is fairly resource-intensive. If we could cut down on the volume of stormwater entering our plants, we could cut down on the costs associated with treating it."
Stormwater can enter the sewerage system a number of ways, but most commonly gets in through illegal plumbing connections and landscaping that diverts stormwater into manholes or overflow relief gullies in people's backyards.
Council is currently undertaking a rigorous program to reduce the volume of stormwater getting in from private properties.
"Our staff use a number of methods to identify where stormwater is getting in, including smoke testing, dye testing, visual property inspections and CCTV sewer inspections," said Ms Coates.
"The amount of illegal connections and other defects we're finding across the region is quite concerning. In some cases these are deliberate and in other cases the problem is inherited and the homeowner has no idea.
"But they all need to be fixed."
Homeowners who are found to have an illegal connection or defect on their property will receive a letter instructing them to have the issue rectified within 90 days.
