Sewer and Stormwater Easements

Sewer and stormwater easements are the most common type of easement on residential land in Australia. If you are buying a block in an established suburb or a new estate, there is a reasonable chance one or both will be present. They are also the easements that most frequently cause building conflicts, because they often run across the rear or through the middle of a block — exactly where many house designs place living areas, alfresco spaces or backyards.

Understanding the difference between sewer and stormwater easements, what each restricts, and how to deal with them before you commit to a house design can save you thousands of dollars and weeks of delay.

Sewer Easements

A sewer easement gives the local water authority the right to access, maintain, repair and replace sewer infrastructure that runs through your property. The pipes may be deep underground — sometimes 1.5 to 3 metres or more — but the authority still needs surface access to excavate if a pipe needs repair.

Sewer easements are typically 1.5 to 3 metres wide, though the width depends on the pipe diameter and depth. The easement width is not the pipe itself — it is the corridor of land that must be kept clear so that an excavator can reach the pipe if needed.

The key restriction is straightforward: no permanent structures with footings are permitted within the easement. This includes houses, garages, sheds, retaining walls with footings, pools, and in some cases even large pergolas. Deep-rooted trees are also restricted because roots can crack or infiltrate sewer pipes.

Stormwater Easements

A stormwater easement protects infrastructure that carries rainwater runoff — either underground pipes or an overland flow path. Stormwater easements are often found on sloping blocks, in low-lying areas, or where a developer has designed a drainage network through an estate.

Stormwater easements can be held by the council or the water authority, depending on your state and location. In some cases, a stormwater easement may also function as an overland flow path, meaning that during heavy rain, water is expected to flow across the surface of your land within the easement corridor.

What You Can and Cannot Do Within the Easement

The restrictions within a sewer or stormwater easement depend on the authority, but the following is a general guide for most Australian water authorities:

Build-Over Approvals

Some water authorities offer a formal build-over-easement approval process. This is not a right — it is a discretionary approval that the authority may grant or refuse based on the specific circumstances.

If approved, you may be required to:

• Provide engineering drawings showing the structure and its relationship to the pipe.
• Install a reinforced concrete slab or protective structure over the pipe.
• Use specific footing designs (e.g. pier and beam) that span the easement without loading the pipe.
• Pay an application fee and ongoing inspection fees.
• Accept that the authority can still access the pipe and may damage the structure during emergency repairs.

Build-over approvals are more commonly granted for minor structures (carports, pergolas, lightweight sheds) than for habitable buildings. They are rarely granted for pools. The process can take 4–8 weeks and there is no guarantee of approval.

How These Easements Affect House Positioning

Sewer and stormwater easements most commonly run along the rear boundary of a block, but they can also run diagonally, along a side boundary, or even through the centre. The impact on house positioning depends on the easement's location and width:

• Rear easement — may push the house forward, reducing backyard space and affecting alfresco positioning.
• Side easement — may prevent side access, double garage on that side, or narrow the building envelope.
• Diagonal or central easement — can make standard house footprints impossible without significant redesign.
• Multiple easements — blocks with both sewer and stormwater easements may have a very limited building envelope.

What This Can Mean for Your Build

If your builder discovers a sewer or stormwater easement conflict after you have already paid for plans, the redesign cost and delay can be significant. If you discover it before committing to a design, you can choose a house plan that fits around the easement from the start — which is almost always cheaper.

What This May Cost

What to Check Before Signing

Questions to Ask Your Builder

Questions to Ask Before Buying the Land

Common Mistakes

• Assuming a rear easement will not matter because the house is at the front — alfresco and backyard structures may still be affected.
• Not checking whether a stormwater easement also carries overland flow, which can affect insurance and safety.
• Assuming a build-over approval will be granted — it is discretionary and not guaranteed.
• Forgetting that easements affect secondary structures (pools, sheds, retaining walls), not just the house.
• Not identifying the correct water authority — different authorities have different rules.

Frequently Asked Questions