Foundation repair projects, whether underpinning, restumping, or drainage correction, often require working in close proximity to underground and underfloor utility services. Water pipes, gas lines, electrical conduits, stormwater drains, and NBN connections can all pass through the zones where foundation work is required. Understanding what disconnections or relocations may be needed, who is responsible, and how to plan for the disruption helps avoid costly surprises and keeps the project on schedule. For a complete picture of the project timeline, see our foundation repair timeline guide.
Quick answer (BLUF)
Foundation repair work near utility services typically requires identification of all service locations before excavation, temporary disconnection of services that pass through work zones, and reconnection after works are complete. NBN connections can be temporarily disconnected and reconnected by a registered telecommunications cabler. Gas and electrical disconnections require licensed tradespeople and, for gas, notification to Jemena (the local gas network operator). Plan for 1-3 weeks of additional lead time for utility disconnections.
Why services matter during foundation repair
Excavation for mass concrete underpinning pits, installation of helical piers through soil, or drainage trench excavation can all damage buried services if they are not located and protected. The consequences of striking a buried service include:
- Gas line: Potentially catastrophic. Gas leaks require immediate evacuation and emergency service attendance. Gas supply to the property is disrupted until repairs are made.
- Water main or service: Water flooding the work area, and supply disruption until repaired.
- Electrical conduit: Risk of electrocution to workers if lines are live. Supply disruption.
- Stormwater/sewer: Flooding with sewage or stormwater. Potential prosecution under EPA regulations if contamination results.
- NBN connection: Loss of internet and potentially phone service while repairs are arranged.
- Dial Before You Dig: This free service (1100 or dialbeforeyoudig.com.au) provides information on the location of underground services registered by network operators. All excavation work, including underpinning pit excavation, should be preceded by a Dial Before You Dig enquiry.
NBN connections and foundation repair
NBN connections enter most Wagga Wagga homes either through a buried pit-to-premises cable (for FTTP or FTTC connections) or through overhead or underground connections to the FTTN node. The relevant points where foundation work can affect NBN connections:
Underground NBN cable: The cable from the street to the premises entry point is typically buried at approximately 300-600 mm depth and follows a route through the property. If an underpinning pit or drainage trench is planned near the path of the cable, the cable must be identified, marked, and if within the working zone, temporarily exposed, supported, or rerouted.
NBN utility box (NTD): The Network Termination Device box is typically inside the home and is not directly affected by subfloor work. However, if foundation repair requires work to the external wall where the NBN service enters the building, the entry conduit and cable may need to be temporarily disconnected.
Temporary NBN disconnection: If the NBN cable must be cut or removed from its path for foundation work, a registered cabler can reconnect it after works are complete. NBN Co does not charge for reconnections in most cases where damage was incidental to construction works, but contractor access time must be scheduled. Allow 5-10 business days for NBN reconnection scheduling.
Mobile hotspot backup: During any anticipated NBN outage associated with foundation work, homeowners can use a mobile data hotspot as a temporary internet connection. In Wagga Wagga, 4G coverage is generally strong in most residential areas.
Gas services
Gas pipes in Wagga Wagga are typically buried to 600 mm depth and serve the meter box on the side of the home. If foundation underpinning pits are required on the same side of the home as the gas meter, or if drainage excavation tracks near a gas service, the gas supply may need to be temporarily interrupted.
Gas disconnection and reconnection must be performed by a licensed gas fitter, and the gas network operator (Jemena, which operates the Wagga gas network) must be notified. Jemena requires advance notice for disconnections and there is a process for arranging temporary isolation. Allow 5-15 business days for scheduling.
Do not attempt to disconnect gas yourself. Gas disconnection without a licensed gas fitter is illegal under NSW law and creates serious safety risks.
Electrical services
The main electrical service cable enters most homes through a meter board, either overhead from the street pole or underground. If foundation work requires excavation in the vicinity of the underground service entry, Essential Energy (which manages the local distribution network in Wagga Wagga) must be contacted and the work area cleared.
Internal electrical conduits embedded in concrete slabs (common in 1970s, 1990s construction) are a specific risk in slab underpinning or resin injection work. Drilling through a slab without knowing conduit locations can damage electrical services and create safety hazards. An electrician should assess conduit locations before any slab penetration.
Water and stormwater services
The water service and stormwater connections pass through the foundation zone in various locations. Before excavation begins, your plumber can assist with locating and marking these services using pipe locator equipment or CCTV.
If foundation work requires temporarily capping a stormwater connection or bypassing a water service, a licensed plumber must undertake these works.
Planning for service disconnections: practical steps
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Include services discussion in your pre-works planning. When receiving quotes, ask each contractor how they identify and manage services and what their process is if a disconnection is required.
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Lodge a Dial Before You Dig enquiry. Do this before any excavation work commences. It is free and typically returns information within 2 business days.
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Budget for disconnection costs. NBN reconnection by a cabler: $150 to $400. Gas disconnection/reconnection: $400 to $800. Electrical works: $300 to $600 for a licensed assessment and conduit marking.
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Add lead time to your project schedule. Service disconnections require advance booking and cannot always be expedited. Add 1-3 weeks to your project timeline to accommodate this.
FAQs
Who is responsible if a utility is damaged during foundation works?
The contractor performing the excavation work has the primary obligation to identify and protect buried services before excavating. If the service was registered on Dial Before You Dig and the contractor failed to check or follow the information, the contractor bears the cost of repair. If the service was not registered and could not reasonably have been identified, responsibility may be shared. Always confirm with your contractor what their procedure for Dial Before You Dig is before work begins.
Can I leave my gas and power connected for the whole project?
In most cases, yes, standard underpinning and restumping work does not require gas or power disconnection unless the work directly intersects with service paths. Your contractor will identify any specific disconnection requirements during the quoting process.
My NBN comes through overhead wires, does this affect anything?
Overhead NBN connections (where the cable runs from the street pole to the fascia of the home) are not affected by subfloor or foundation work unless ladders, scaffolding, or heavy equipment could foul the cable entry point at the fascia level. Alert your contractor to the overhead connection so they can take appropriate care.