Blocked drain

A blocked drain occurs when material builds up inside a pipe or fitting and restricts the passage of wastewater, leading to slow drainage, gurgling, bad smells or overflowing fixtures. Common causes include accumulated fat, food waste, hair, wet wipes, sanitary products, tree root ingress and structural defects such as displaced joints. In older London terraces, particularly across Camden, Islington and Westminster, clay drains laid in the Victorian era are especially prone to root intrusion and partial collapse. Building Regulations Part H1 sets out the minimum design standards intended to reduce blockage risk in new work. Clearance is typically carried out by qualified engineers using rods, high pressure water jetting or mechanical augers in accordance with industry practice. Persistent or recurring blockages usually indicate an underlying defect that benefits from a CCTV drain survey.