Drain Mapping
Know What Lies Beneath
Most older properties in the UK don’t have an accurate record of their drainage system. Over the years, extensions are built, patios are laid, and manholes get buried.
Drain mapping is simply the process of creating a clear, up-to-date plan of your underground pipes.
In simple terms: We find out exactly where your drains run, How deep accessible points are, and where they go—so you don’t have to guess.
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Why Do You Need a Drain Map?
You generally don’t need a map if everything is working fine. However, you definitely need one if you are planning construction work. Digging “blind” can lead to expensive accidents or legal issues.
Our customers usually ask for mapping when:
- Planning an extension: You need to know if that new kitchen wall is going to sit right on top of a sewer pipe.
- Buying a house: To check if the drainage is shared with a neighbour (which affects your liability).
- Getting permission: Architects and Water Authorities (like Thames Water) often require a map for “build-over” agreements.
- Solving a mystery: If you have persistent flooding or smells but can’t find the manhole, it might be buried under the lawn.
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How We Create the Map
We don’t just guess. We use a combination of high-tech cameras and tracing equipment to locate accessible parts of your system.
1. The Camera Survey (CCTV) – We send a specialist crawler camera down your pipes. This shows us the layout from the inside and lets us see if the pipes are carrying waste (foul water) or rainwater (surface water).
2. Electronic Tracing (Sonde & CAT) – This is the clever part. We attach a small transmitter to the camera. As it moves underground, we track its position from above ground using a handheld scanner. This allows us to mark the path of the pipe across your garden or driveway.
3. Dye Testing – If pipework is not accessible, or joins blind, we can use dye to confirm where they connect.
4. The Final Plan – Once we have all the data, we draw up a clear plan for you. This will show:
- The route of the drains.
- The location of all manholes (even the buried ones).
- The direction the water flows.
- Pipe depths and sizes where accessible.
What We Can Find
A mapping survey often reveals surprises that save you money later, such as:
- Shared drains: Pipes that serve your neighbours as well as you.
- Hidden manholes: Access points that have been paved over or buried under flowerbeds.
- Cross-connections: Where rainwater is wrongly going into the sewer (or vice versa).
- Defects: Cracks or tree roots that need fixing before you build over them.
Who Is This For?
- Homeowners planning renovations, conservatories, or extensions.
- Home Buyers who want to know what they are inheriting.
- Architects & Builders who need accurate plans to design foundations.
- Commercial Sites that need to update their site records.
The Benefits
- Avoid Accidents: Prevents builders from accidentally striking a live pipe.
- Get Approved: Smooths the process with Building Control and Water Authorities.
- Save Money: It is much cheaper to map a drain than to move a foundation halfway through a build.
- Peace of Mind: You know exactly what is under your feet before you start digging.
It is one of the most valuable services for planning and pre-construction works.
Testimonials
What Our Clients Say
“I called at 08:10 hours to report a blocked drain. A little while later, Darren rang to tell me he’d arrive in half an hour. He arrived on time and resolved the problem quickly and without fuss. He was polite and friendly throughout. Within two hours of reporting the blockage, all was well. Thank you.” Customer, Surrey
“I unreservedly recommend ASL. All the glowing reviews of ASL are true. They had to lift paving slabs to fix my drains, and I was concerned there might be unavoidable damage. I should not have worried. Liam and Richard did a superb job. Thanks, ASL” Customer, Surrey
“Darren arrived very promptly and got to work quickly. He did an excellent job and explained what he was doing. We would have no hesitation in recommending ASL Services.” Customer, Surrey
“Very efficient to book them to sort out a sewer drain blockage, and the cost was exactly what they quoted. Called before they arrived with a clear ETA. Got on with the job and sorted it out within the hour. Darren was excellent – very courteous and helpful, did more than we expected to help sort the problem out and was a font of knowledge on all things sewer-related. Given the subject matter (eeew) the whole experience with ASL was an absolute pleasure.” Customer, Surrey
“ASL recently carried out a drain repair at our house. They responded quickly to the call for help, came out and soon diagnosed the problem – tree roots blocking the drain. The remedial work on site was carried out by Lester and George – they worked hard and were very thorough. This is a long-established company that seems to know what they are doing.” Customer, Surrey
Areas we cover
Surrey, Hampshire, Berkshire, West Sussex and South West London
The ASL Limited HQ is in Guildford, but our operating area is the whole of Surrey and parts of Berkshire, Hampshire, West Sussex and South West London.
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Contact Us
Get in touch today
You can call us on 0800 181 684, email info@asllimited.co.uk or use the form below:
