The 1200mm height rule
Pool barriers must be at least 1200mm high at every point, measured from finished ground level on the outside of the fence — the side a child would approach from. That measurement is where pools fail: garden beds built up against the fence, new paving, or soil settlement can quietly shave 100mm off a once-compliant barrier.
Where a boundary fence forms part of the barrier, a higher standard applies — commonly 1800mm. See the boundary fence guide.
The 100mm gap rule
No opening anywhere in the barrier may allow a 100mm sphere to pass through. In practice, inspectors check:
- The gap under the bottom rail — max 100mm from finished ground
- Spacing between vertical bars or palings — max 100mm
- Gaps where the fence meets posts, walls or gates
- Holes dug by pets or erosion under the fence line
Non-climbable zones
The standard requires a 900mm "non-climbable zone" measured in an arc from the top of the barrier — on the outside, and for some barrier types the inside too. Within that arc there must be nothing a child could use as a foothold or handhold:
- Pot plants, outdoor furniture, BBQs and eskies
- Retaining walls, steps and raised garden beds
- Tree branches and sturdy shrubs
- Pool equipment — pumps, filters, heaters
- Horizontal fence rails (unless spaced 900mm+ apart or shielded)
"Climbable" is where inspector judgement comes in — a flimsy shrub might pass while a woody one fails. When in doubt, move it before the inspection.
The most common height/gap fails aren't construction errors — they're landscaping and time. New turf, mulch build-up, subsidence and pet excavation all change the measurements. Re-check yearly with a tape measure.
Where these numbers come from
All states build on Australian Standard AS 1926.1 (safety barriers for swimming pools), adopted with local variations and different effective dates. The numbers above hold nationally for barriers built or modified in the last decade; older pools may be assessed against the standard of their era — Victoria formalises this by construction date. Your state page has the specifics.