Quick answer: Before digging any fence post holes, confirm the boundary, request current underground-service information, identify visible water and drainage points, and mark every post and gate position. The right footing plan depends on the fence height, material, soil, slope and site conditions.
Fence planning often starts with the finish: timber or Colorbond, a privacy screen or a new gate. The part that deserves equal attention is below ground. A post hole can intersect a service, disturb drainage or land in the wrong place if the boundary and site layout have not been checked first.
This checklist is designed for homeowners in Melbourne's south-east and the Mornington Peninsula who are planning a new fence, replacement fence, gate or related outdoor structure.
1. Check underground services before digging
Fence posts, gate posts and retaining structures all involve excavation. Start with Before You Dig Australia to request available plans for underground infrastructure near the work area. The service is a useful first step, but plans are not a substitute for careful excavation, site observation and any further locating work the project requires.
Walk the boundary and note the position of:
- water meters, gas meters and electrical boxes
- stormwater pits, sewer inspection openings and drainage grates
- outdoor taps, irrigation lines and downpipe connections
- telecommunications pits, conduits and other visible service markers
Do not rely on the old fence line alone. A previous fence may have been installed off the boundary, around an obstruction or without a clear record of underground services.
2. Look for water, drainage and outdoor-tap constraints
Water and drainage issues can affect both the position of the fence and the long-term condition of the posts. Avoid covering inspection openings, blocking a designed drainage path or placing a footing where it will make future maintenance difficult.
Pay particular attention where the fence will meet an extension, deck, retaining wall, driveway or outdoor entertaining area. If you find a damaged outdoor tap, a leaking pipe, poor drainage or a connection that needs to be moved before the fence is built, arrange plumbing advice before excavation. For a plumbing-specific issue in the area, see the South East Melbourne plumbing guide.
The plumbing reference is a separate resource for a related property issue, not a substitute for confirming your own service locations or obtaining the right advice for the site.
3. Confirm the boundary and intended fence line
Before setting out posts, confirm where the fence is meant to sit. Check the title information and any available site plans, then compare them with existing paths, driveways, retaining walls and the old fence. If the boundary is uncertain or a neighbour disagrees, pause the work and obtain appropriate surveying or legal advice before installing a permanent structure.
Also confirm who is responsible for the fence, how gates will open, and whether access is needed from either side during construction or future maintenance.
4. Mark every post, gate and service point
Once the line is understood, mark the corners, ends, changes in direction, gate openings and intermediate post centres. Use a string line where practical and leave enough room to check the line from more than one angle.
A good set-out should answer these questions before the first hole is dug:
- Where do the corner and end posts sit?
- What clear opening is needed for each gate?
- Will the gate swing into a path, driveway or drainage area?
- Are there trees, roots, rock, fill or retaining structures in the post line?
- Can materials and tools reach the work area without damaging existing surfaces?
5. Match the footing plan to the site
There is no single post-hole depth that suits every fence. A solid Colorbond panel, an open timber fence, a pool barrier, a tall privacy screen and a gate structure all place different demands on the posts and footings.
Review the likely conditions before choosing a footing approach:
- Fence height and material: taller and more enclosed fences can experience greater wind load.
- Soil: sand, clay, rock and recently disturbed fill behave differently during excavation and installation.
- Slope: a sloping block may need stepped panels, retaining work or a different set-out.
- Coastal exposure: salt air and wind can affect material selection and maintenance.
- Existing structures: nearby walls, paving and drainage may limit the available footing width.
Use the site conditions to decide whether a simple residential footing is suitable or whether the project needs a more detailed assessment before installation.
When to pause and get help
Stop before excavation if you are unsure about a boundary, cannot identify a service, find standing water, hit unexpected rock, or need to alter drainage. It is usually easier to resolve the issue before materials are ordered and posts are set.
A fencing contractor can also help confirm the practical set-out, post spacing, gate positions and construction access. For a site-specific fencing discussion across the Mornington Peninsula and Melbourne's south-east, contact The South East Fencer.
Pre-dig checklist
- Confirm the intended boundary and fence responsibility.
- Request available underground-service plans through Before You Dig Australia.
- Walk the site and mark meters, pits, taps, drains and visible service points.
- Check for water, drainage, irrigation, rock, roots, fill and retaining structures.
- Mark corners, ends, gates and post centres before excavation begins.
- Confirm gate clearances, construction access and future maintenance access.
- Choose materials and footing details for the fence height, soil, slope and exposure.
- Pause and obtain the right advice if any service, boundary or drainage detail remains uncertain.
Common questions
Do I need to check services for ordinary fence posts?
Yes. Fence posts still require excavation, and even a small hole can damage an underground service. Request the available plans and use safe excavation practices before work begins.
Can a plumber locate every underground service?
No. A plumber may help with water or drainage questions, but electrical, telecommunications, gas and other assets need to be considered separately through the appropriate service and locating process.
Can a new fence affect drainage?
It can if posts, concrete footings or retaining work obstruct an existing flow path, cover an access point or change how water moves across the block. Check the layout before installation and address any drainage concern early.
What should I do if the old fence is not on the boundary?
Do not assume the old line is correct. Pause the set-out and obtain suitable surveying or legal advice before placing a new permanent fence.