Drain Mapping and Drain Tracing

Drain mapping shows where the pipes under a property actually run, how deep they are and where they join. It answers practical questions: can I build here, which drain is mine, and where is the fault the camera found? We trace drains with a CCTV camera and a sonde, a small transmitter that lets us follow the camera from the surface. Call 07427 195142 to talk it through.

What drain tracing involves

The camera goes in through a chamber, gully or rodding point and is pushed along the pipe. Behind its head sits a sonde, which gives off a signal. Above ground, a locator picks up that signal and shows both the position and the depth of the head. As the camera moves, we mark the line on the ground with paint or pegs, and note every bend, junction and chamber on the way.

Where a pipe cannot take a camera, for example a small rainwater pipe, a sonde can be pushed on rods instead. Dye or running water from each sink, toilet and downpipe confirms which outlet joins which run.

When a drain mapping survey helps

Most people ask for drain mapping before building work. An extension, conservatory or garage built over a drain needs planning around it, and building standards will want to know what is there. It is also useful when two properties disagree about a shared drain, when a defect has been found on camera and has to be dug out in the right place, or when an older house has no plans at all. Our guide to building over a drain in Scotland explains the approvals involved.

• Before an extension, drive or garden landscaping
• Finding the exact spot of a defect seen on camera
• Settling which pipes are private and which are shared
• Locating a lost or buried inspection chamber
• Checking where surface water and foul water go

What you get

A drainage mapping survey ends with a plan of the system: the route of each run, chamber positions, depths where they were taken, pipe sizes, direction of flow and where each appliance connects. Where the camera picks up a defect on the way, it is marked on the plan and shown in the footage. If you only need the route of one pipe, we can trace just that run.

For a full condition report alongside the plan, a CCTV drain survey covers the state of every pipe in detail. Our guide to drain tracing and mapping explains how the two fit together.

Foul water, surface water and shared drains

Many homes have two separate systems: one for toilets and sinks, one for rain. Others have a single combined pipe. Mixing them up when new work is connected causes trouble later, so tracing confirms which is which before anything is joined in. If you are planning a new connection, see sewer connections.

On terraces and in older streets a drain often serves several houses before it reaches the sewer. Mapping shows where your pipe joins the shared run, which is useful when working out who is responsible for a blockage. Our guide on who is responsible for a blocked drain covers the rules.

Access and preparation

We need to reach at least one chamber or access point, ideally the one nearest the house, and be able to run water in every sink, toilet and outside tap. If a run is blocked, it has to be cleared before the camera can go through, which we can do on the same visit with rods or drain jetting.

Questions