Utility location and mapping
Find what is really in the ground before you dig
Record plans show roughly where pipes and cables should be. A utility mapping survey finds where they actually are on your site, using ground penetrating radar and cable locators, and gives you a drawing your architect, engineer and groundworker can work from.
Plans tell you what should be there. A survey shows what is.
Network operators' plans are records, not measurements. Positions can be out by a metre or more, depths are rarely shown, and private pipes and cables, such as the supply to an outbuilding or an old drain, are not on them at all.
On a residential plot that matters most where you are about to dig: foundations for a new home or extension, a new driveway or access, connection trenches and soakaways. Hitting a cable or gas pipe is dangerous, and finding an unexpected drain or water main can mean a redesign or a diversion.
The Health and Safety Executive's guidance on avoiding danger from underground services (HSG47) expects anyone digging to use plans and to locate services on site before excavating. A mapping survey does both, properly, and records the result.
Useful for
- New homes and self-build plots
- Extensions near drains and sewers
- Infill and garden plots
- Conversions with new service routes
- Driveways, access and dropped kerbs
- Planning where new connections will run
What the survey includes
Each survey is scoped to your site and what you are building. A typical residential survey covers the following.
Records search first
The asset owners' plans for every utility are gathered before the visit, starting at least three working days ahead, so the team knows what should be there.
Cable locators
Electromagnetic locators sweep the site for live cables and metal pipes, and trace services from stop taps, lamp posts and cable risers. Routes are marked on the ground as they are found.
Ground penetrating radar
Radar scans at close intervals, typically every 2 to 5 metres, confirm the locator routes and pick up plastic pipes, ducts and drains a locator cannot find.
Drains and chambers
Manholes and inspection chambers are lifted from the surface, with no one going inside. Pipe sizes and chamber details are recorded and drain runs traced with rods and a sonde.
Fixed to the map
Everything found is surveyed with a total station and GPS to Ordnance Survey grid and levels, so it drops straight onto your architect's drawings.
Drawing and report
AutoCAD (DWG) and PDF drawings with a survey report. Each service shows its type, approximate depth and how confidently it was located.
Surveys to PAS 128
Surveys follow PAS 128:2022, the British Standards specification for detecting, locating and verifying underground utilities, and the RICS guidance on measured surveys of land, buildings and utilities. PAS 128 sets out the survey types: a desktop search of records, a reconnaissance of the site, detection with locators and radar, and verification by digging trial holes.
For most residential sites, a records search with detection on site gives the right balance of cost and confidence. Where a service runs right where you plan to build, trial holes can confirm its exact position and depth. We agree the right level with you before the survey is booked.
Topographical and drainage surveys
Surveys are often combined in one visit, which saves time and cost.
- Topographical survey: buildings, boundaries, kerbs, trees, manholes and a grid of levels, tied to Ordnance Survey grid and datum. It is usually needed anyway to present the utilities on, so doing both in one visit makes sense.
- Drainage survey: drain runs and condition, often needed before a build-over agreement for an extension near a public sewer.
- Access and visibility: visibility splays for a new access, where planning asks for them.
Every service gets a quality level
The drawing shows how each service was found and how close its position is likely to be, so your designer knows which lines to trust and where a trial hole is worth it.
| Level | How it was found | Typical position | Typical depth |
|---|---|---|---|
| B1 | Radar and a cable locator both agree | Within about 150 mm | Within about 15% |
| B2 | Found with one method only | Within about 250 mm | Within about 40% |
| B3 | Weak signal, or no depth reading | Within about 500 mm | Not given |
| B4 | Route assumed from records | No tolerance | Not given |
Results depend on the ground, the type of pipe or cable and access. Where an exact position matters, trial holes can verify it.
From quote to drawing
Send us the site and the area you need surveyed. A plan with it marked in red is ideal.
Before the survey
The survey area needs to be accessible, overgrown ground cleared and manhole covers free to lift. Plans and site details are needed at least 48 hours before the visit. We check all of this with you when we quote.
- 1
You send the site
Address, a plan with the survey area marked and what you are planning to build.
- 2
We quote a fixed price
For the survey extent you need, with any topographical or drainage survey added if useful.
- 3
Records, then the site visit
The records search starts a few days ahead. A two-person team then traces, marks and surveys the services on site.
- 4
You get the drawings
AutoCAD and PDF drawings with a survey report, ready for your design team and groundworker.
Plans, survey and connections in one place
Utility plans pack
The record plans for every utility around your site, if you only need the records.
Order plansSite report and budget
Where each new connection can go, the risks and an estimated cost for each utility.
See the reportNew connections
The applications for water, sewer, electricity, gas and broadband, managed for you.
ConnectionsUtility mapping questions
What is a utility mapping survey?
A survey on site that finds and records the underground pipes and cables, using cable locators and ground penetrating radar, and draws them up so you can design and dig around them safely.
Do I need one if I already have the utility plans?
Plans are records, not measurements. Positions can be out, depths are rarely shown and private services are missing. A survey shows what is actually in the ground where you plan to dig.
How accurate is it?
Each service gets a quality level. Found by both radar and a locator (B1), it is typically within about 150 mm across and 15% of its depth. Found by one method only (B2), within about 250 mm. Trial holes can verify a service exactly where it matters.
Does anyone go down the manholes?
No. Manholes and inspection chambers are lifted and inspected from the surface, and drain runs are traced with rods and a sonde.
Can radar find plastic pipes?
Often, yes. Ground penetrating radar can pick up plastic pipes, ducts and drains that a cable locator cannot, although results vary with soil conditions and depth.
What do I receive?
AutoCAD (DWG) and PDF drawings tied to Ordnance Survey grid and levels, with a survey report. Each service shows its type, approximate depth and quality level, and routes are marked on the ground during the survey.
Can you do a topographical or drainage survey at the same time?
Yes. Combining surveys in one visit usually saves time and cost. A drainage survey is often needed before a build-over agreement for an extension near a public sewer.
How much does a survey cost?
It depends on the size of the area, the access and what is included. We quote a fixed price for your site before anything is booked.
Know what is in the ground before you dig
Send us the site and the area you need surveyed. We will come back with a fixed price for the survey.