What utilities must be disconnected before demolition?

Disconnecting services is one of the first and most important steps in a safe demolition. Live gas, electricity and water can turn a routine job into a disaster. This page sets out which utilities must be dealt with and how.

Which services must be made safe

Every live service feeding a building is a hazard during demolition and must be dealt with before work begins. The main ones are:

• Gas: a live gas supply is one of the most dangerous, with a risk of explosion. The supply must be disconnected and made safe by the appropriate party before demolition.
• Electricity: live cables carry a risk of electric shock and fire. The electricity supply must be isolated and disconnected, and overhead or buried cables crossing the site identified.
• Water: a live water supply risks flooding the site and undermining the works. The supply must be disconnected to prevent uncontrolled water.
• Drainage and sewers: drains and sewers serving the building may need to be sealed or removed so the demolition does not damage or block the wider network.
• Telecoms and other services: telephone, broadband and any other lines should be disconnected or removed.

Leaving any of these live during demolition exposes workers and the public to serious danger, so making the building "dead" is a foundational safety step.

Who arranges disconnection and why it matters

Disconnections must be arranged through the relevant providers, not improvised on site. This matters for both safety and legality:

• Gas and electricity: these are dealt with by the network operators and suppliers responsible for the connection. Cutting a gas pipe or electricity cable yourself is extremely dangerous and not acceptable — the supply must be properly isolated and disconnected by competent people.
• Water: the water company handles disconnection of the supply.
• Drainage: sealing or removing sewers and drains may need to be coordinated with the sewerage undertaker and done as the council requires.

Because these involve third parties, disconnections often take time to schedule — sometimes weeks. They should be requested early in the project, not left to the last minute. A competent demolition contractor will usually coordinate the disconnections as part of planning the job, but the responsibility for ensuring services are made safe before work starts rests with those running the project.

How disconnection links to the notices

Utility disconnection is woven into the formal demolition process, not separate from it. The Section 80 demolition notice under the Building Act 1984 is served not only on the local authority but also on the gas and electricity suppliers, precisely so that the services can be addressed before the building comes down. In turn, the council's Section 81 counter-notice can require steps such as the sealing of sewers and drains and confirming that services are disconnected.

So the sequence joins up: you serve the notice, the relevant parties are made aware, disconnections are arranged with the providers, and the council's conditions on drains and services are met — all before demolition starts. Allowing enough lead time for the providers to act, and building the disconnections into the programme alongside the asbestos survey and the notice period, is the practical way to keep a demolition both safe and on schedule. A building with all its services safely isolated is far less hazardous to take down than one still connected to the grid and mains.

The dangers of leaving services live

To understand why disconnection comes so early in the process, it helps to be clear about what can go wrong if a service is left live during demolition:

• Gas: a damaged live gas supply can leak and ignite, causing fire or explosion — one of the most serious risks on any demolition site.
• Electricity: live cables, whether within the building or buried and overhead on the site, can cause electric shock, electrocution and fire if struck by tools or machinery.
• Water: an uncontrolled water supply can flood the works, undermine excavations and create unsafe conditions underfoot.
• Drainage: damaged drains and sewers can release foul water, cause contamination and block the wider network.

These hazards are entirely avoidable by making the building "dead" before work starts. That is why disconnection is treated as a foundational step rather than something to be dealt with as the work proceeds. It also explains why the disconnections must be done by the network operators, suppliers and water company — they have the means to isolate supplies safely, which is not something to improvise on site.

Coordinating disconnections in the programme

Because disconnections depend on third parties and can take time, they need to be managed as part of the overall demolition programme. A practical approach is:

• Identify all services early: establish which utilities serve the building, including any buried or overhead cables and shared services with neighbouring properties.
• Request disconnections in good time: contact the providers well in advance, since scheduling can take weeks rather than days.
• Tie in with the Section 80 notice: serving the notice on the gas and electricity suppliers is part of making them aware so the supplies can be addressed.
• Meet any council conditions: deal with the sealing of sewers and drains as required by any Section 81 counter-notice.
• Confirm before starting: verify that every service has been safely disconnected before demolition begins.

A competent demolition contractor will usually take the lead on coordinating these steps, but the responsibility for ensuring the building is fully isolated rests with those running the project. Treating utility disconnection as an integral, early part of the plan — not a last-minute task — is what allows the demolition to proceed safely, with the structure cleanly separated from the gas, electricity, water and drainage networks before any of it is brought down.

Disconnection within the wider demolition process

Utility disconnection is best understood not as an isolated chore but as one strand of the wider preparation a demolition needs. It connects to several of the other steps, and seeing those links helps explain why it has to be planned early:

• With the Section 80 notice: the notice is served on the gas and electricity suppliers precisely so they are aware the building is to be demolished and the supplies can be addressed.
• With Building Control's conditions: a Section 81 counter-notice can require sewers and drains to be sealed, tying drainage work into the council's requirements.
• With the asbestos survey and removal: both sit in the same early window of the programme, and a competent contractor schedules them together so nothing is left to the last minute.
• With the CDM 2015 planning: making services safe is part of planning the demolition so that the principal hazards are controlled before work starts.

Because all of these depend on third parties and have their own lead times, the realistic message is that a demolition needs to be planned as a set of parallel strands started well in advance, with utility disconnection among the first. A building that is still connected to live gas, electricity, water and drainage is far more dangerous to demolish than one that has been cleanly isolated. Treating the disconnections as an early, integral part of the plan — coordinated with the notice, the council's conditions, the asbestos work and the safety planning — is what allows the building to be brought down safely, lawfully and without the avoidable hazards that live services create.

Frequently asked questions

Sources & further reading

• HSE — demolition
• GOV.UK — Building Act 1984, section 80 (legislation)

Figures on this page are typical UK ranges drawn from published sources and depend on your specific building. They are guidance, not a quotation.