Sometimes, foreign objects such as household refuse; illegally-dumped rubbish from manholes; rubbish swept or blown into damaged manholes; and storm water runoff from streets and footpaths entering leaking manhole covers, enters pipelines in the system. Groundwater, silt and sand can also enter pipelines through cracks or poorly-constructed joints.
Sewer pipes can overflow due to stormwater entering from road-and-street runoff. A large influx of water during heavy rainstorms can also overload sewage treatment plants. Sewerage systems can be designed to overflow in predetermined locations so that overflows can be controlled and their impact minimized.
Breakage of sewer pipes sometimes occurs because of soil movement, disintegration due to age, and indiscriminate digging. Broken sewer pipes obstruct sewerage flow and may result in manholes and toilets overflowing.
Broken public sewer pipes are automatically repaired by Indah Water while broken private connections are the responsibility of individual property owners and can be repaired by private contractors. Alternatively, Indah Water's assistance can be obtained in getting a contractor to repair them.