When Do You Need a Permit to Dig? (UK Guide)

A permit to dig is a formal authorisation that must be in place before anyone breaks ground — whether that is mechanical excavation, hand digging, post-hole boring, or even driving a stake into the ground. You need one whenever there is a credible chance of striking a buried service (electricity, gas, water, telecoms, or fibre) or of an excavation collapsing. In practice, that covers almost any ground penetration on or near a developed site.

This guide covers UK requirements and references HSE guidance. Legislation and standards may differ in other jurisdictions. It does not constitute legal advice and is not a substitute for site-specific assessment by a competent person.

What is a permit to dig?

A permit to dig (sometimes called an excavation permit or a ground disturbance permit) is a site-specific control document. It confirms — in writing, before work starts — that the buried services in the dig area have been identified, located, and marked, and that the excavation can proceed safely. It is issued by a competent person with direct knowledge of the location, the services present, and the detection methods used.

The permit is the last line of defence in a longer process. By the time it is signed, the planning, surveys, service drawings, and trial holes should already be done. The permit records that those steps actually happened and that the person doing the work has been briefed on what is below the surface.

It is worth being clear about the difference between a permit to dig and a general permit to work. A permit to dig is one specific type within a wider permit-to-work system — the one that controls ground penetration. The umbrella system decides which activities need a permit at all; the permit to dig is the document for the digging itself.

When is a permit to dig required?

The trigger is risk, not depth. A shallow scrape in a car park can hit a buried cable just as easily as a deep trench. A permit to dig is typically required when any of the following apply:

• Mechanical excavation — using an excavator, trencher, or auger anywhere services could run
• Hand digging near known or suspected services — hand tools reduce but do not remove the risk of a strike
• Post-hole boring, piling, or driven stakes — point-loads that can pierce a cable or pipe
• Horizontal directional drilling or coring — blind boring where the path is not visible
• Any work breaking ground near roads, footways, buildings, or known utility corridors

If the only thing standing between a worker and a live 11kV cable is "we think it's clear over there," that is exactly when a permit forces the question to be answered properly.

The legal and guidance framework

There is no single Act titled "Permit to Dig." Instead, the duty to control excavation work comes from several sources working together.

HSG47 — Avoiding danger from underground services is the key practical reference. It sets out a three-element safe system of work for any excavation: plan the work, locate and identify buried services, and excavate safely. HSG47 is aimed at everyone involved in commissioning, planning, managing, and carrying out work on or near underground services. A permit to dig is the standard way to document that this safe system has been followed.

The Construction (Design and Management) Regulations 2015 (CDM) create the legal duties. Regulation 22, headed "Excavations," requires "all practicable steps" to prevent danger from collapse, dislodged material, and burial — including supports or battering where necessary. Regulation 22 also requires that the excavation and any equipment or materials affecting its safety are inspected by a competent person at the start of each shift, after any event likely to affect stability, and after any unintended fall of material.

The Management of Health and Safety at Work Regulations 1999 require a suitable and sufficient risk assessment, which the permit references rather than replaces.

For street and highway works specifically, undertakers also have duties under the New Roads and Street Works Act 1991, but for most contractors the HSG47 plus CDM combination is what drives the permit-to-dig requirement on private sites.

What goes on a permit to dig

A permit to dig should record the safe-digging process, not just a tick that says "services checked." The sections that matter most:

Location and scope

Precise dig location, depth, and method. "North compound" is not enough — "north compound, between gridlines C and D, trench 0.8m deep for new drainage" is. The permit applies to a defined area and a defined task.

Service identification

This is the section the whole permit exists for:

• Utility drawings obtained — record plans from the relevant service owners, with their dates
• CAT and Genny survey completed — cable avoidance tool scan results, who carried it out, and when
• Services marked on the ground — spray-marked or pegged, matching the drawings
• Trial holes / safe digging — hand-dug inspection pits to confirm the position and depth of services before machine digging
• Known unknowns — any area where services are suspected but not confirmed, and the controls for it

Controls and method

• Permitted dig method (hand dig within an agreed distance of services, machine dig only outside it)
• Support or battering arrangements to prevent collapse
• Exclusion zones and barriers around the open excavation
• Emergency arrangements if a service is struck

Inspection record

A daily inspection log tied to the CDM Regulation 22 requirement: inspector name, date, condition of supports and walls, water ingress, and edge protection. Each inspection signed.

Authorisation and close-out

Two signatures — the person carrying out the work and the competent person authorising it — at issue. At close-out, confirmation that the excavation has been backfilled or made safe, and the area handed back.

Permit to dig vs excavation permit: are they the same?

In most UK practice the terms are used interchangeably, and many sites run a single document covering both the buried-services risk and the collapse/stability risk. If you already use a general excavation permit that includes service identification and CDM Regulation 22 inspections, you have a permit to dig — the label matters less than the content. Our excavation permit template guide walks through a combined version section by section.

Where the two can diverge: some larger sites issue a high-level "permit to dig" for the ground-disturbance authorisation and a separate detailed excavation method statement. For a small contractor, one well-structured permit is usually enough.

Common mistakes

Relying on drawings alone. Utility records are frequently wrong, incomplete, or out of date. Drawings tell you where services were recorded, not where they actually are. A CAT scan and trial holes confirm reality.

Permitting the area, not the depth. A permit that authorises "digging in zone B" without specifying the safe-dig distance from located services invites a machine bucket straight through a cable.

Skipping the daily re-inspection. Ground conditions change overnight — rain, vibration from adjacent plant, or a partial collapse. CDM Regulation 22 requires inspection at the start of each shift, not just on day one.

One permit for the whole job. A two-week dig that moves across a site is not one permit. As the dig advances into new ground with different services, the assessment — and the permit — needs to keep up.

Paper vs digital

Permit-to-dig records carry a lot of specific data: service drawings, CAT survey results, trial-hole findings, and daily inspection logs. On paper, this is spread across separate forms that are hard to cross-reference, and the buried-services plan rarely travels with the permit. A digital system can attach the marked-up drawings and CAT survey photos directly to the permit, prompt the daily Regulation 22 inspection automatically, and keep every version time-stamped and searchable.

PermitPad is building digital permit templates — including excavation and ground-disturbance permits — with structured service-identification fields, photo capture, and daily inspection prompts. Join the waitlist to try it when it launches.

Key references

• HSG47 — Avoiding danger from underground services (HSE) — the three-element safe system of work for excavation
• Construction (Design and Management) Regulations 2015, Regulation 22 — excavation duties and competent-person inspection
• Management of Health and Safety at Work Regulations 1999 — risk assessment requirement
• HSG250 — Guidance on permit-to-work systems (HSE) — how permits fit into a wider system

For the full picture of how different permit types fit together, see our types of permit to work guide.