Well-functioning sewers are critical to public health, clean water and urban safety — yet they tend to go unnoticed when they work reliably and attract attention only when problems surface. The challenge is to keep these hidden systems running under mounting pressure: ageing pipes, heavier storms and stricter pollution.
Sewage overflows and spills are a problem in every city and county. They are causing environmental pollution when sewage overflows reach rivers, lakes and seas. When sewer ruptures are occurring, they cause damage of property, traffic disturbances and are expensive to repair. Better sewer maintenance would make sewer management less costly, reduce its environmental impact and improve city environment.
However, for better planning, better data about the current condition of the sewers is needed. Currently, AS Tallinna Vesi, which owns and manages most of the sewer 2400 km network on Tallinn, manages to pressure-wash about 150-200 km of pipes and inspect about 45 km of pipes with a remotely operated camera. Most of the works planned on sewer networks is based on the estimates of the sewer condition by experts or are emergency repairs. Currently, emergencies (ruptured pipes, leaks, blockages) constitute about 30% of all maintenance work in the city.
