Pool Installation Underground Services: The Pre-Excavation Checklist

What's Typically Buried Under Your Backyard

Suburban Australian blocks commonly contain six types of underground service:

• Sewer pipes

• Stormwater pipes, which are normally separate from the sewer

• Water supply pipes

• Gas services

• Electricity cables running between the street supply and the home

• Telecommunications cables, including NBN, Telstra and other networks
  
  

The material, size, depth and alignment of these services vary between properties. Older pipes may be clay, copper or other materials, while newer services are more likely to use PVC, polyethylene or modern cable systems.

Older or rural blocks may also contain:

• Septic tanks and trench fields

• Bore-water lines

• Irrigation mains

• Private electrical cables

• Old or abandoned services

• Homemade plumbing installed by a previous owner who considered plans optional
  
  

If you hit telecommunications, sewer or stormwater infrastructure, the job will stop and repairs can become expensive. If you damage gas or electricity infrastructure, somebody could be seriously injured or killed.

Never assume a service follows the shortest route or sits at a standard depth. Underground services are not always known for respecting common sense.

Before You Dig Australia: The Free Service Nobody Should Skip

Before You Dig Australia, commonly called BYDA and formerly known as Dial Before You Dig, is a free national enquiry service.

You lodge the proposed work area at byda.com.au. The enquiry is sent to participating asset owners that may have infrastructure near the excavation.

Plans often arrive quickly, but allow up to two business days for responses. For a pool project, we recommend lodging the request at least five working days before excavation. That gives you time to review every response, speak with the excavator or installer and arrange further locating if needed.

There is one important catch. The plans are indicative, not definitive.

They may show:

• The general path of the underground service

• The type of infrastructure

• The asset owner

• Safety instructions and contact details

• The material, size or depth where that information is available
  
  

They do not necessarily show:

• The exact location or depth

• Unmapped private services

• Infrastructure owned by organisations that do not participate in BYDA

• Recent changes or abandoned services

• Every branch running from a main service to a building
  
  

BYDA gets the investigation underway. Confirming the exact position and depth, and finding anything that is not mapped, may require a competent private locator and physical verification through potholing or non-destructive digging.

Work health and safety requirements generally require current information about underground essential services to be obtained and made available before excavation. BYDA is an important part of that process, but the exact legal requirements vary between jurisdictions and asset types.

Underground services may also need to be considered in the site plans, engineering documents or approval information for the project. Our pool council approval guide for Australia explains what the council assessor, certifier or building surveyor may need to see.

Pre-excavation checklist

Before the excavator turns up, work through this list:

• Lodge a BYDA request at least five working days before the dig

• Review every plan returned and mark the dig area against them

• Paint-mark located services on the lawn using the standard colour codes

• Not connected to sewer? Locate your septic tank and trench field before excavation.

• Confirm the operator has the printed plans on site the day of the dig

Who actually runs BYDA on your job?

This is where the two buyer paths split.

If you are DIYing the installation

If you are hiring the excavator and other trades directly, confirm whether you or the excavation contractor will lodge the enquiry.

Do not assume the contractor has already handled it.

The online enquiry itself is straightforward. Once the responses arrive:

• Forward every plan and instruction to the excavation contractor.

• Discuss any services close to the pool footprint.

• Confirm who will arrange further locating.

• Keep the plans available on excavation day.

Save the digital copies somewhere you can find them quickly. Excavation day is not the ideal time to search through 4,000 unread emails.

If you are using an installer

A licensed installer may handle BYDA as part of the normal pre-excavation preparation. If you are using your own installer or one from CFPK’s referral network, ask them to confirm this before work begins.

Ask to see the plans and find out how any nearby services will be managed.

A good installer will walk you through the service locations and explain whether further locating or potholing is required. If the installer cannot produce the plans or explain who reviewed them, that is a red flag.

Service-by-service locating guide

Each service creates different risks, but none should be located through guesswork.

Gas

Gas is a high-risk service. Newer installations may include tracer wire or warning tape, but older services may have neither. Do not rely on those features being present.

If a gas service is damaged, stop work, move everybody away and call the gas network emergency number from a safe location. Call 000 if there is an immediate danger.

Electricity

Underground electricity cables may run between a street pillar, connection point, switchboard, shed or other structure.

They do not always follow a perfectly straight line, particularly when a property has been renovated or additional buildings have been added. If the plans or site conditions are unclear, have the cable located and follow the electricity distributor’s instructions before excavation.

Never treat a cable as safe because it appears old or unused.

Water

A property may contain both water-authority infrastructure and privately owned pipes running from the meter to the house, sheds, gardens or other fixtures. Private water lines may not appear on BYDA plans.

Damaging one can cause flooding, soil movement and loss of water to the home. Repairs may be straightforward in some cases, but they are considerably less enjoyable when the excavation is filling with water.

Sewer

Sewer pipes may be clay, PVC or another material, depending on the property’s age.

Their depth and alignment vary. Do not assume the pipe follows the fence or sits at a predictable depth.

Cracking a sewer can involve contamination, clean-up, inspections and licensed repairs. It can also stop excavation until the line is made safe.

Telstra, NBN and other telecommunications

Telecommunications cables can be surprisingly shallow and may be difficult to see during excavation.

Cutting one may disconnect your home or several properties, depending on the cable and network layout. Reinstatement can also cost considerably more than joining two loose ends together.

Your neighbours may still send Christmas cards, but the message inside could become a little pointed.

Stormwater

Stormwater pipes vary in depth, material and direction.

A damaged pipe can lead to poor drainage, erosion and water movement around the pool or house. The problem may not become obvious until the next decent downpour.

Do not dismiss stormwater as less important simply because it does not contain sewage.

When to engage a private locator

BYDA plans may be enough to show that the proposed pool is clear of known infrastructure, but further locating is worthwhile when uncertainty remains.

A private locator is particularly useful when:

• BYDA plans show a service crossing or running close to the pool footprint.

• You need a more accurate location before choosing the pool position.

• The block is older or rural and may contain unmapped services.

• Private water, electricity or irrigation lines are likely.

• The plans do not match what you can see on site.

• The excavation is deep or close to known infrastructure.

• The asset owner requires locating or physical verification.
  
  

Private locators may use electromagnetic locating equipment, ground-penetrating radar or a combination of methods.

No single method finds every service. Potholing or non-destructive digging may still be needed to confirm the exact position and depth before machine excavation nearby.

A private locator may cost roughly $400 to $800 as a planning indicator, although the actual price will depend on the region, property size, number of services and locating methods required.

If you are DIYing, ask your excavation contractor whether they have a locator they regularly use. If you are using a full-service installer, ask who they use and whether locating is included in the quote.

Either way, the cost can be cheap insurance compared with repairing a damaged service.

When the News Is Bad: Service Re-Routing

Sometimes the BYDA plans come back and the sewer main is running diagonally through your pool footprint. The fly in the ointment. Now what?

Re-routing a buried service to clear the pool is a real job, licensed plumber for sewer or water, licensed sparky for electricity, the gas authority for gas mains. It is not uncommon for a mains service relocation to cost between $10,000–$30,000 depending on the service, the distance involved, and how cooperative the asset owner is.

Walk through the options first:

• Shift the pool. Cheaper than shifting the pipe nine times out of ten. A 1–2m relocation can clear a sewer run entirely; just confirm the new position still respects pool placement setbacks from boundaries, easements and the house.
• Re-route the service. If the pool cannot move because of setbacks, slope or the shape of the block, the service may need to move. This can require licensed work, asset-owner approval, updated plans and inspections. Make sure the quote clearly explains what is included.
• Abandon and recap. An old private service may sometimes be decommissioned and capped, but only where the asset owner or relevant authority permits it. Do not cut and cap a service because it looks abandoned. An unloved pipe can still be doing a surprisingly important job.

Who Pays If Something Gets Hit

Even with BYDA plans and a careful operator, accidents can happen.

Who pays will depend on the contract, who was responsible for the BYDA enquiry, what information was available before excavation and whether the asset owner’s instructions were followed. It may also come down to whether locating or potholing should have been completed, what caused the strike and what the relevant insurance policies actually cover.

Do not assume your excavation contractor’s public liability insurance automatically covers every service strike.

If you are managing the job yourself, confirm before work starts who will lodge and review the BYDA enquiry, who will arrange any locating or potholing and who will keep the plans on site. You should also ask what the contractor’s insurance covers and how damage to both located and unmapped services will be handled.

If you are using an installer, the contract should clearly explain who is responsible for the BYDA enquiry, service locating and physical verification. It should also explain how damage to identified and unmapped services will be handled and what insurance applies.

The clause you do not want is one that says nothing about underground services and allows every cost to flow straight back to you. Read the contract. It is not as exciting as choosing the pool colour, but it is usually cheaper.

What to Do If a Service Is Hit During Excavation

Nobody wants this moment. If it happens, the protocol is the same whether it's your shovel or the installer's:

1. Stop work immediately. No further machine movement until the situation is assessed

2. Identify the service. Gas (smell, hissing), water (visible flow), electricity (visible cable, possible spark), sewer (smell), telecommunications (cable colour codes)

3. Make safe. Gas: clear the area, call the gas authority emergency line. Electricity: don't touch, call the energy provider emergency line. Water: shut off at the meter

4. Notify the utility. Each utility has a 24-hour damage-report number, it's printed on the BYDA plans

5. Document everything. Photos, time, location, witnesses. The damage-report process needs them

6. Don't repair it yourself. Even if you know how. The repair must be done by the utility or a licensed contractor
   
   

By utilising free services like Before You Dig Australia and engaging private locators when necessary, you ensure that your pool installation proceeds without the "fly in the ointment" of a buried utility strike.

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Frequently Asked Questions

Can excavation start before every BYDA response arrives? No. Wait until all expected responses have arrived and been reviewed before excavation begins. Each asset owner may provide different plans, safety instructions or locating requirements. Starting after receiving only one or two responses could leave the operator unaware of another service running through the work area.

What if the pool position changes after lodging the BYDA enquiry? Submit a new or updated enquiry covering the revised excavation area. Do not assume plans requested for the original position automatically cover the new pool location. Review the new responses and arrange further locating if any service now sits close to the excavation.

Do I need to check areas outside the pool shell excavation? Yes. Consider every area where the ground will be disturbed, including plumbing and electrical trenches, the equipment pad, excavator access and any location used for posts or footings. A service does not need to run through the pool hole itself to affect the project.

What if BYDA returns no plans for my property? No returned plans do not guarantee that the property is clear. Private services, abandoned infrastructure and assets owned by organisations that do not participate in BYDA may still be present. Inspect the site carefully and consider a competent locator where the property history or visible connections suggest underground services.