Community protection General advice

If your drain is blocked you'll usually know because your waste will stop going away when you flush the toilet, or gullies outside will overflow. There will also probably be a smell. 

The owners of a house are solely responsible for maintaining a private drain, clearing blockages and repairing any faults in it. If the blockage occurs in the public sewerage system, then it's the responsibility of the water and sewerage company to fix it.