Can I build over an existing drain on my property? +
Building over or near a public sewer requires a Build Over Agreement from your water company. For private drains, you do not need permission but you must ensure the drain remains accessible for maintenance. Building Regulations require that drains under or near buildings are adequately protected. A CCTV drain survey before and after construction is strongly recommended to prove the drain's condition.
What should I do if my drain is overflowing outside? +
If an external drain or manhole is overflowing, check whether it is a shared drain serving multiple properties. Since October 2011, lateral drains and public sewers became the responsibility of your water company, so contact them first if the blockage is beyond your property boundary. If it is a private drain within your boundary, call a drainage engineer in London to clear the blockage.
What equipment should a professional drainage engineer have? +
A properly equipped drainage engineer should have high-pressure water jetting equipment (typically 3,000+ PSI), a CCTV drain camera for surveys, electro-mechanical cleaning machines, drain rods, and root cutting attachments. They should also carry personal protective equipment (PPE) including gloves, eye protection and waterproof clothing. Be wary of anyone who turns up with just a set of drain rods — they will struggle with anything beyond a minor blockage.
How often should I have my drains surveyed? +
For most domestic properties, a CCTV drain survey every 3 to 5 years is sufficient to catch problems early. If you have mature trees near your drains, older clay pipes, or a history of blockages, consider annual surveys. You should also commission a drain survey before buying a property — it can reveal expensive problems like collapsed sections or root intrusion that are not visible from the surface.
What is the difference between a drain and a sewer? +
A drain serves a single property and runs from your house to the boundary. A sewer carries waste from multiple properties and is maintained by the water company. Lateral drains — the section connecting your drain to the public sewer — transferred to water company responsibility in October 2011. Understanding this distinction matters because it determines who pays for repairs.
What causes a foul smell from my drains in London? +
Foul drain smells are usually caused by a dried-out trap (the U-bend), a cracked or disconnected pipe, or a blockage building up in the system. If the smell is coming from outside, it could indicate a broken manhole cover seal or a collapsed section of drain. Run water through any infrequently used sinks or showers to refill their traps first. If the smell persists, a CCTV drain survey will identify the cause.