Who This Guide Is For
Owner-builders and homeowners about to have plumbing, electrical or stormwater trenches dug; small builders coordinating trades on a rebuild; and anyone who has been told “we can't dig yet, locates aren't back” and wants to know whether that is a real reason or a stalling tactic. It is a real reason.
This is general guidance, not legal or safety advice. Requirements differ between asset owners, so the instructions on the plans you receive always beat anything you read here. For trench depths and how trenching fits into a build program, see our Melton plumbing and electrical trenching guide.
What the Service Actually Is
Dial Before You Dig is now branded Before You Dig Australia, though nobody on site calls it that. Ring 1100 or lodge online, describe where you intend to dig, and the service refers your enquiry to registered asset owners whose infrastructure sits in that area. Each of them sends you plans for their own network. It is free, and it is a referral service — not an inspection, not a guarantee, and not a permit.
On a typical block in Melbourne's west you might hear from an electricity distributor, a water corporation, a gas network operator, a telecommunications carrier and sometimes council or a rail authority, depending on how close you are to their assets. Which organisations respond depends entirely on your address, so read the covering emails rather than assuming.
Important: only registered asset owners are captured. Anything not registered, and anything on the private side of the meter or pit, will not appear.
What the Plans Don't Tell You
This is where most people get caught. Plans are indicative records, and they have real limits:
- Depth is generally not shown, and where it is, treat it as historical. Road resurfacing, regrading and landscaping change cover over the years
- Horizontal position is approximate. A line drawn confidently through a nature strip can sit a metre or more from where it was drawn
- Private services are invisible. Irrigation, pool pump lines, a sub-main to a shed or granny flat, garden lighting, an old sewer branch, whatever a previous owner ran themselves — none of it is on any plan
- Abandoned assets may still be in the ground, and live ones are occasionally missing from records altogether
- New estate networks change fast. In growth corridor stages, services can go in between your enquiry and your dig date
On established blocks around Melton, Werribee or the inner west, the private-side services are usually the bigger risk. On new estate lots the bigger risk is a freshly installed main that is not on a plan yet.
Plans tell you something is probably there. Only exposing it tells you where it is.
The Proper Sequence on a Real Build
Done properly, it runs like this:
- Lodge the enquiry covering the whole dig area, not just the trench line — include the crossover, the spoil stockpile area and anywhere machines will track
- Read every response. Some asset owners attach conditions, contact requirements or supervision rules to their plans
- Book a private locator where the plans show assets near your trench, or where the property is established and private services are likely
- Mark the ground — paint or pegs, so the operator is looking at marks rather than a PDF on a phone
- Pothole to prove depth at the points where your trench crosses or runs close to a located asset
- Then dig, hand digging inside the zones the asset owner specifies and keeping the plans on site
Allow at least two full business days between lodging and needing the machine, and more if a locator has to attend. On a build program, the sensible slot is straight after the site cut is finished and before your plumber and electrician want to be in the ground.
Proving Depth: Potholing and Vacuum Excavation
Potholing means carefully exposing an asset before mechanical excavation goes near it, so you know exactly where it sits in three dimensions. Two common methods:
Hand digging. Slow, cheap, perfectly adequate for a shallow domestic service in soft ground. Use insulated tools where an electrical asset might be present, and dig with care rather than force.
Vacuum or hydro excavation. A specialist truck cuts a hole with water or air and sucks out the material, exposing the service without touching it. It is the right call near a gas main, a high-voltage cable, a water main or a bundle of telecommunications conduit — and near some assets it is the only method the owner will accept.
Hitting rock complicates this on the western plain, because a hammer near a located asset is not an option. If your trench line runs through basalt, see what happens when you hit rock and plan the locating accordingly.
Hand-Dig Zones and No-Go Areas
Asset owners set their own clearance rules and they vary by asset type and voltage or pressure. In practice you will see requirements like a hand-dig-only zone extending a set distance either side of a marked asset — often in the range of a few hundred millimetres — with mechanical excavation prohibited inside it. Some high-pressure gas and transmission assets require notification, supervision by the asset owner, or a formal permit before anyone digs nearby.
Do not average out conflicting figures or rely on what worked on the last job. Take the number from the plans for that specific asset on that specific site, and brief everyone who will be in the trench.
If Something Does Get Hit
The priority is people, not the pipe. Broadly: stop work, keep everyone clear, and do not attempt a repair or to move the machine if it is in contact with an electrical asset. Gas escapes mean evacuating upwind, eliminating ignition sources and calling emergency services and the asset owner immediately. Water, sewer and telecommunications strikes are less dangerous but still get reported to the asset owner straight away.
Financially, a strike is not just the repair. It can mean network outage costs, traffic management, emergency attendance, program delay and, where reasonable care was not taken, liability that insurers will scrutinise closely. That is the whole reason a competent operator refuses to dig on assumptions.
What to Expect From Your Earthmoving Contractor
We turn up with our own machines and operators, which means the person deciding how close to work to a marked cable is the same person who quoted your job. On any trenching work, that means:
- Plans on site and current before the machine starts
- A walk around the block looking for pits, meters, vents, inspection openings and patched trench lines that hint at something the plans missed
- Hand digging or vacuum excavation where the asset owner requires it, quoted honestly rather than skipped to win the job
- Working from your plumber's or electrician's marks, and stopping to ask when something does not match
- Photos of the open trench before backfill, which is your record of depth, bedding and clearances
If a contractor offers to “just have a careful dig” without locates, that is your answer about how the rest of the job will run. Compare that against the checks in our guide to choosing an earthmoving contractor.
When to Call a Contractor
- Two weeks before you want trenches open, so locating and any potholing fits in the program
- When your plumber and electrician have finalised service runs and can mark them out
- When plans show something near your trench line and you want advice on whether a locator is needed
- On any established property where you have no idea what a previous owner buried
We trench across Melton, Caroline Springs, Werribee, Tarneit, Craigieburn and greater Melbourne, alongside site cuts and truck work on the same job. See earthmoving in Melton for local work, and call if you want a straight answer on sequencing. English, Arabic or Turkish on site if that helps your crew.
FAQs
Is it still called Dial Before You Dig?
The service is now branded Before You Dig Australia, but almost everyone on site still says Dial Before You Dig, and 1100 still works. It is a free referral service: you lodge details of where you plan to dig, and registered asset owners send you plans for their infrastructure in that area.
How long does an enquiry take to come back?
Some asset owners respond almost immediately by email and others take a couple of business days, so allow at least two full business days before you need the machine on site. If you also need a private locator to mark the ground, add time for them to attend.
Do the plans show how deep a pipe or cable is?
Generally no. Plans show approximate horizontal alignment, not reliable depth. Ground levels change over decades of roadworks and landscaping, so the only way to know the true depth of an asset is to expose it carefully by hand digging or vacuum excavation before machine work starts.
Do I need a private service locator as well?
Often yes, particularly for deeper trenches, work near a pit or main, or anything on an established property. Plans tell you roughly what is in the street; a locator using electromagnetic equipment or ground penetrating radar marks it on the ground where the bucket can see it, and can pick up unregistered private services the plans never mention.
Who lodges the enquiry — me, my plumber or the earthmoving contractor?
Whoever is planning the excavation should lodge it, and on most builds that means it gets done by the builder or the trade specifying the trench. What matters is that a valid enquiry exists, the plans are on site, and everyone working in the trench has seen them. We will not put a bucket in the ground without them.
How long are the plans valid for?
Not indefinitely. Asset owners generally treat a referral as current for a limited window — commonly around 30 days — because networks get extended and new services go in, especially in growth corridor estates. If your dig date slips by a month, lodge a fresh enquiry rather than reusing old plans.