NUAR maps 3.2 million kilometres of infrastructure

Ordnance Survey has marked a year operating the National Underground Asset Register, with more than 400 public and private asset owners now contributing information on buried infrastructure across England, Wales, and Northern Ireland.

NUAR brings underground pipes and cables into a secure, standardised digital map intended to support excavation planning, infrastructure maintenance, and emergency work. The system now contains more than 3.2 million kilometres of mapped assets and covers over 80 per cent of known underground infrastructure in the three nations where it operates.

Use of the platform has increased by 115 per cent by transaction volume since Ordnance Survey took operational responsibility in 2025. More than 230 supply-chain contractors can access information on behalf of asset owners, while all electricity distribution network operators and water companies have signed up.

Participation among public authorities has also grown. More than 70 per cent of local authorities and 90 per cent of highway authorities are contributing data, giving contractors and designers a broader view of the infrastructure that can affect roadworks, utility installations, drainage, foundations, and other excavation-heavy construction activities.

The underlying problem is not new. Project teams preparing to break ground can be dealing simultaneously with electricity, gas, water, telecommunications, drainage, and other buried services owned by different organisations, historically supplied through separate records and in inconsistent formats.

Bringing those records into one system reduces the administrative work required to establish an initial view of a site. Ordnance Survey says users can access NUAR data and visual information in around 60 seconds, replacing a process that can otherwise involve gathering and reconciling plans from several asset owners.

That does not turn the platform into a substitute for established safe-digging procedures. Site investigation, service locating, trial holes, permit systems, and physical verification remain necessary because mapped information cannot prove that an unrecorded asset is absent or that every historic record precisely reflects conditions underground.

The value is earlier visibility. On road, utilities, housing, commercial, and civil engineering projects, a buried service discovered late can force alterations to drainage, foundations, duct routes, access arrangements, or temporary works after design and procurement have progressed.

Earlier access to consolidated information allows those interfaces to be considered before plant and labour arrive. Trial-hole positions can be planned more deliberately, excavation methods selected around known hazards, and designers can assess whether utility diversions or protection measures are likely to affect the programme.

That is particularly relevant on congested urban sites. A relatively small excavation can intersect several layers of infrastructure installed at different periods, while road closures and restricted working areas leave limited room to change sequence once construction begins.

NUAR has also moved beyond its original status as a voluntary digital programme. The Data (Use and Access) Act received Royal Assent in 2025, placing the register on a statutory footing and updating legislation governing the sharing of underground asset information.

The next policy step is to establish NUAR as a comprehensive statutory register across England, Wales, and Northern Ireland. That will place greater emphasis not only on whether an asset owner contributes data, but also on whether records are maintained consistently enough to remain useful as networks change.

Data quality will ultimately matter as much as volume. A digital platform containing millions of kilometres of infrastructure is of limited value if updates lag behind new installations, diversions, and abandoned assets, particularly on sites where small positional errors can change an excavation method or require additional investigation.

Integration with existing safe-dig services is developing alongside the statutory framework. The Government Digital Service agreed a memorandum of understanding with Linesearch BeforeUdig in June 2026, while Ordnance Survey is working with other service providers rather than positioning NUAR as an isolated replacement for established industry processes.

Evidence from early users also moves the system beyond a database exercise. Contractors and utility operators are applying the common mapping view during planning and excavation preparation, allowing project teams and asset owners to work from the same underlying information rather than separate collections of plans.

For construction businesses, the practical benefit is most likely to appear in pre-construction and site preparation rather than as a visible piece of equipment. Fewer hours spent obtaining records, earlier identification of clashes, and more consistent information for subcontractors can reduce uncertainty before excavation reaches the critical path.

Ordnance Survey puts the potential long-term economic benefit at at least £400 million a year through increased efficiency, fewer accidental strikes, and reduced disruption. That figure depends on the system becoming routine working infrastructure rather than an additional map that project teams consult inconsistently.

A year into Ordnance Survey’s operational role, NUAR has reached sufficient scale to influence how underground constraints are identified before work begins. The remaining challenge is less about adding another headline million kilometres and more about ensuring the information is current, complete, and embedded in the decisions made before the first excavation starts.