Water mains, sewer upgrades, pump stations and utility relocations share a common risk profile: deep or confined excavations near live services, groundwater, and customers who expect minimal disruption. This guide covers the plant, sequencing and compliance questions that shape a well-scoped hire for utility network work.
01 / Excavation and trenching plant
Pipeline and network work is built around excavators matched to trench depth and working space. Compact 5 to 8 tonne machines suit property connections and narrow streets, 12 to 14 tonne machines cover most reticulation mains, and 20 to 30 tonne machines are needed for deep sewers, large diameter trunk mains and pump station excavations. Tilt hitches, trenching buckets, hydraulic hammers and compaction wheels are standard attachments, and a rock saw or larger hammer may be justified where hard ground is expected.
Horizontal directional drilling, microtunnelling and pipe bursting are increasingly used to avoid open trenching under roads, rail lines or waterways. Those methods are generally delivered by specialist contractors with their own rigs, but the supporting plant often comes from hire suppliers: excavators for launch and receival pits, vacuum excavation trucks, drilling fluid mixing and recycling units, generators and lighting. Scope that support plant separately from the specialist rig so it is not assumed to be someone else's responsibility.
02 / Trench support and dewatering
Trenches deep enough to present a collapse risk need engineered protection such as trench shields, slide rail systems or hydraulic shoring, selected to suit depth, soil type, groundwater and pipe length. Shoring hire specialists can often provide engineering support, installation guidance and certification for their systems. Confirm whether the supplier will provide design documentation or whether your own engineer must verify the arrangement, and check that the excavator is heavy enough to install and extract the shoring safely.
Groundwater and stormwater inflow are common on utility projects, particularly in low-lying and coastal areas. Options range from submersible pumps in the trench to wellpoint spear systems and deep well pumps where inflow is significant. Discharge water may need settling, filtering or testing before release, depending on approvals and the requirements of the local authority or environmental regulator. For residential streets or overnight operation, ask about noise-attenuated pumps and generators to reduce complaints.
03 / Working around live services
Utility work almost always involves excavation beside other assets: gas, electricity, telecommunications and existing water or sewer infrastructure. A BYDA enquiry is the starting point, but plans are not always accurate, so potholing with non-destructive vacuum excavation to confirm location and depth is standard practice on most networks. Vacuum excavation trucks are frequently hired for this task, and they are also used wherever an asset owner prohibits mechanical excavation within a set distance of critical infrastructure.
Many asset owners set clearance distances and supervision requirements for work near their assets, including high-voltage cables and high-pressure gas mains. Plant working near overhead powerlines must stay outside the applicable approach distances or operate under a documented plan with spotters, as set by the state regulator and network operator. Brief suppliers on these constraints so they can recommend suitable machines, such as zero tail swing excavators, and operators with genuine experience working near live services.
04 / Shutdowns, connections and bypass pumping
Connecting new mains or sewers to live networks usually requires planned shutdowns or bypass pumping, scheduled by the utility and notified to customers well in advance. The plant for these works must be on site, tested and ready before the shutdown starts, because any delay is felt directly by households and businesses. Plan redundancy for critical items such as bypass pumps and generators, and confirm the supplier can supply standby units or respond quickly if a pump fails mid-operation.
Sewer bypass deserves particular care. Pumps must be sized for peak flows, with suction and discharge lines routed safely and protected where they cross traffic or footpaths. The utility may specify level monitoring, alarms or continuous attendance during bypass. Ask suppliers about their bypass experience, request the pump curves for the units offered, and agree how refuelling and maintenance will be handled when the operation runs through nights and weekends.
05 / Compliance, reinstatement and commercial points
Utility clients commonly require contractors to be prequalified, to follow the client's safety and environmental standards and to complete site-specific inductions. Excavation deeper than 1.5 metres is generally treated as high-risk construction work requiring a SWMS, and entry into pits, manholes and wet wells may be confined space work requiring gas detectors, ventilation and retrieval equipment. Include that ancillary equipment in the hire request so it arrives with the main plant rather than as an afterthought.
Reinstatement of roads, footpaths and nature strips usually has to meet local authority standards, which brings small rollers, plate compactors, asphalt saws and profilers into the job near the end. Check minimum hire terms on shoring and pumps, because these items are often left in place longer than planned. Also ask about cleaning and decontamination charges for pumps, hoses and shoring returned after use in sewage or contaminated ground, which can be significant.
Field checklist
- Match excavator size to trench depth, working space and shoring installation needs.
- Confirm who provides shoring design or verification for each trench configuration.
- Pothole and verify live services with vacuum excavation before mechanical digging.
- Plan standby pumps and generators for shutdowns and bypass operations.
- Include gas detectors and confined space equipment in the hire request where needed.
- Check cleaning and decontamination charges for pumps and shoring.
- Allow for reinstatement plant that meets local authority standards.
Frequently asked questions
What shoring do I need for a trench?
The system depends on trench depth and width, soil type, groundwater and surcharge loads such as nearby traffic or spoil heaps. Common options include trench shields, slide rail systems and hydraulic struts. A competent person should assess the ground and select the system, and some arrangements require engineering certification. Shoring hire specialists can usually recommend suitable options for the conditions you describe.
When is vacuum excavation required?
Vacuum excavation is commonly used to expose and confirm underground services before mechanical digging, and asset owners may require it when work is close to critical infrastructure such as high-pressure gas or high-voltage cables. It also suits confined or sensitive areas where a conventional bucket could damage assets. Check the asset owner's conditions, which often accompany BYDA responses.
How do I size a pump for sewer bypass?
Bypass pumps are sized from the peak flow of the section being bypassed, the suction lift and the total head the pump must work against, including pipe length and elevation changes. The utility may supply flow data or specify the design. Supplier technical staff can match pump curves to the duty, and standby capacity is usually recommended in case of failure.
Are there extra charges for returning dirty pumps and shoring?
Many suppliers charge cleaning fees for pumps, hoses and shoring returned with sewage, sludge or heavy soil, and decontamination may be charged separately where hazardous material is involved. These charges are usually listed in the hire terms. Ask about them at quotation stage and consider cleaning equipment on site where practical before it goes back.