The householder is responsible for the whole drainage system up to where it joins the sewer, where a house is drained individually.
The local council is responsible for cleansing any part of a communal system, if they were constructed prior to 1937. However the council can reclaim the cost of repair from the householders. Systems constructed after 1937 are the sole responsibility of the householders. They must collectively share the cost of repairing and cleansing the drain up to the sewer.
If unsure, contact the Technical Services Department of your local council to determine responsibility for the drainage system.
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