Most conveyancing due diligence on the Central Coast focuses on title, zoning and a standard building and pest inspection. A question that comes up far less often, but that can materially affect what a buyer can do with a property, is whether a council or Hunter Water/Central Coast Council sewer asset runs through the land, whether any structure has been built over or near it without the required encasement, and what that means for the buyer once settlement happens. This guide is written for conveyancers, buyers and their advisers who want to know what to actually check.
What a sewer encasement is, and why it exists
Where a structure, a pool, a garage, a home extension, is built over or close to an existing sewer main or a private sewer line carrying flow from more than one property, the relevant water or council authority typically requires the section of pipe under or near that structure to be protected. Encasement means the pipe is enclosed in a reinforced concrete surround, or in some cases fully replaced with a stronger pipe class, so that the load of the structure above it doesn’t crack or crush the pipe over time. Encasement is a standard, well-understood engineering requirement, not a red flag in itself. The issue for a buyer is not that encasement exists, it’s whether it was actually done, done to standard, and properly documented and approved when the structure went up.
Where this becomes a conveyancing issue
A sewer main or a shared private sewer line can run across a residential lot for reasons that predate the current owner, and sometimes predate the current subdivision layout entirely. On the Central Coast, this comes up most often on:
- Older subdivisions from the 1960s-80s where a sewer main was laid along the rear or side boundary of a block before later infill development added structures closer to it than would be approved today.
- Battle-axe and dual-occupancy blocks, where a shared private drainage easement often runs down one side of the property to reach the street connection, and a garage, carport or deck has since been built across or very close to it.
- Waterfront and near-lake properties (Tuggerah Lakes suburbs, Brisbane Water foreshore) where council stormwater and sewer infrastructure sometimes sits closer to the building envelope than the block’s apparent size would suggest.
- Older strata and multi-dwelling sites where a shared sewer main serving several units runs beneath a driveway, carport or covered parking area added after the original subdivision.
If a previous owner extended a house, added a pool, or built a garage over or near a sewer asset without obtaining the water authority’s or council’s consent, and without the pipe being properly encased, that defect doesn’t go away at settlement. It becomes the new owner’s structure sitting over the new owner’s compliance problem.
What a Section 10.7 (planning) certificate does and doesn’t tell you
A Section 10.7 certificate (the current NSW planning certificate, previously known as a Section 149 certificate) will typically note if a property is affected by a registered easement for drainage or sewerage, and may flag council infrastructure in the vicinity. What it generally will not tell you is:
- The exact depth, condition or age of the pipe itself
- Whether a structure built over or near the asset was actually approved by the relevant authority
- Whether any encasement work that was supposed to happen actually occurred, or was done to the required standard
- Whether the asset is a main serving multiple properties (typically the authority’s asset) or a private line serving only this lot (the owner’s responsibility)
The certificate is a starting point for identifying that an easement or asset exists. It is not a substitute for physically confirming the pipe’s condition and position, which is what a CCTV inspection is for.
What to check before exchange
For a conveyancer or buyer working through due diligence on a property with a registered sewer easement, or any older Central Coast property where a pool, garage or extension sits close to a rear or side boundary:
- Request the Section 10.7 certificate and the deposited plan. Confirm whether a sewerage or drainage easement is registered, and its width and location relative to existing structures.
- Ask directly whether any structure was built over or within the easement, and if so, request the development consent or the water authority’s encasement approval from the vendor or their solicitor.
- Commission a CCTV inspection of the private line and, where accessible, the section running near or under the structure in question. This is the only way to see the actual pipe condition, its depth, and whether visible encasement or protective works are present.
- Clarify who owns the asset. A main serving multiple lots is typically the water authority’s or council’s responsibility to maintain; a private line serving only this property is the owner’s. Get this in writing where the answer isn’t obvious from the deposited plan.
- Factor unresolved encasement issues into negotiation. Where a structure has been built over an asset without documented approval, rectification, which can mean partial demolition, excavation and pipe protection works, is a real cost that should be reflected in price or addressed before settlement.
What this means if you’re the seller
If you’re selling a Central Coast property with a pool, garage or extension built close to a known sewer line, having a CCTV inspection and any historical council or water authority approvals ready for a buyer’s solicitor removes a point of friction that can otherwise stall a sale during due diligence. A vendor who can produce this documentation upfront, rather than have a buyer discover the issue mid-negotiation, is generally in a stronger position at exchange.
What it costs to resolve
| Item | Approximate Cost |
|---|---|
| CCTV inspection of a private sewer line near a structure | $250–$450 |
| Combined CCTV inspection and written asset location report | $350–$600 |
| Point repair where encasement or pipe damage is confirmed | $1,800–$3,500 |
| Full reline of an affected section (no-dig, where the pipe is intact) | $5,500–$12,000 |
| Excavation and encasement of a non-compliant section | Project-specific, quoted after CCTV |
Where the existing pipe is structurally sound and simply needs protection brought up to standard, drain relining is frequently a lower-disruption option than full excavation, though a genuinely under-strength or damaged section sitting beneath a structure sometimes does need to be exposed and properly encased rather than lined.
Frequently asked questions
What’s the difference between an easement and an encasement? An easement is the legal right registered on title allowing a pipe (and access to it) to exist across a property, regardless of who owns the land above it. Encasement is the physical engineering measure, typically a concrete surround, protecting the pipe itself from load where a structure sits over or near it. A property can have an easement without needing encasement, and vice versa, depending on what’s built above the pipe.
Our Section 10.7 certificate doesn’t mention a sewer easement. Does that mean there isn’t one? Not necessarily. The certificate reflects what is registered and known to council at the time it’s issued, but older easements are sometimes poorly documented, and a private line serving only one or two properties may not appear on the certificate at all. Checking the deposited plan and, where there’s any doubt, commissioning a CCTV inspection is the more reliable way to confirm what’s actually there.
We’re buying a property with a pool built close to the rear boundary. Should we be concerned? It’s worth checking. If the pool was approved through a normal development application process, the certifier should have required confirmation that any nearby sewer asset was adequately protected before approving the pool. If the work predates formal council oversight, or approval documentation can’t be produced, a CCTV inspection of the affected section is a sensible step before exchange.
Who pays to fix a non-compliant encasement discovered after settlement? Generally, the new owner, unless the contract specifically allocates this risk to the vendor or the defect can be shown to have been actively concealed, which is a high legal bar. This is the core reason to identify and document the issue before exchange rather than after. For the full framework on using CCTV findings in negotiation, see our guide to negotiating price after a bad drain report.
Does this apply to new builds as well as older properties? Yes, though less commonly. Where a new build has been constructed near an existing sewer main, the encasement and approval requirements are the same, and any shortcuts taken during construction can still surface later. Our guide to new-build drain defects covers the broader pattern of construction-related drainage issues worth checking during a defect liability period.
Book a CCTV drain and sewer asset inspection before you exchange →