Sites that fall away from the street often cannot drain stormwater to the road by gravity. The usual answer is a drainage easement through a downhill neighbour’s land to a council pipe or street, and NSW councils commonly make that easement a deferred commencement condition, or a condition to be met before the construction certificate, on duplex and townhouse DAs. If the neighbour will not agree, section 88K of the Conveyancing Act 1919 allows the Supreme Court to impose an easement. Section 40 of the Land and Environment Court Act 1979 allows the Land and Environment Court to do the same where a development appeal is before it or has been determined. The court must be satisfied that the easement is reasonably necessary for the effective use or development of the benefiting land, that the use is not inconsistent with the public interest, that the burdened owner can be adequately compensated, and that all reasonable attempts were made to obtain it by agreement. For developers, it is a last resort with real cost and time, and it should be identified in due diligence, not discovered after consent.
Key takeaways
- Downhill sites that cannot drain to the street by gravity typically need an inter-allotment drainage easement over a neighbouring lot, or an alternative such as a pump-out system where the council accepts it.
- Councils frequently impose the easement as a deferred commencement condition, so the consent does not operate until the easement is registered.
- Under section 88K of the Conveyancing Act 1919, a court may impose an easement that is reasonably necessary for the effective use or development of the benefiting land, if the public interest, compensation and reasonable-attempts tests are met.
- The Land and Environment Court can impose an easement under section 40 of its Act where it has determined, or has before it, a Class 1 development appeal, applying the section 88K tests.
- Even if every test is met, the power is discretionary, and the applicant pays compensation and usually the costs.
Who this is for: developers and builders with dual occupancy, townhouse or subdivision sites that slope away from the street in Western Sydney, the Hills, the Central Coast and the Illawarra, who need to understand the stormwater easement options before buying or lodging.
Why do downhill sites need a drainage easement?
Councils’ stormwater policies and DCPs require roof and surface water to be discharged lawfully to the street kerb, a council pipe or a natural watercourse. On a lot that falls to the rear, gravity drainage to the street may be impossible without filling the site or pumping. The practical options are:
| Option | When it works | Drawback |
|---|---|---|
| Inter-allotment drainage easement over a downhill neighbour | A downhill lot connects to a council pipe or street | Needs the neighbour’s agreement or a court order; compensation and works on their land |
| Existing easement already benefiting the lot | The 88B instrument already provides one | Capacity and condition must be checked |
| Charged or pump-out system to the street | Where the council’s policy allows it, often limited to certain situations | Ongoing maintenance and failure risk; many councils discourage it for new development |
| On-site absorption | Sandy soils, some rural and regional areas | Rarely acceptable on Western Sydney clay soils |
The common mistake is buying a downhill duplex site on the assumption that a pump-out will be approved. Check the council’s stormwater policy first.
How do councils condition a drainage easement?
Where a DA relies on an easement that does not yet exist, councils commonly use a deferred commencement condition: the consent does not operate until the applicant provides evidence that the easement has been created and registered. Others impose the requirement before the construction certificate. Either way, the consent cannot be built until the easement is in place. Planning panel reports in NSW describe the next step when the easement cannot be obtained by agreement: an application to the court.
A deferred commencement consent has a time limit for satisfying the deferred matters, so a stalled easement negotiation can put the consent at risk. Build that time into the program.
What does the court need to be satisfied of?
Commentary on recent Land and Environment Court decisions summarises the section 88K tests. The court may only impose an easement if satisfied that:
- the easement is reasonably necessary for the effective use or development of the land that will benefit;
- the use of the benefiting land will not be inconsistent with the public interest;
- the owner of the burdened land, and anyone else with an interest, can be adequately compensated for any loss or disadvantage; and
- all reasonable attempts have been made by the applicant to obtain the easement.
“Reasonably necessary” does not mean absolutely necessary, but it requires more than convenience. In one 2026 decision, the court imposed a stormwater easement over a neighbouring strata property for a childcare development after a deemed refusal appeal, finding it reasonably necessary and accepting an $85,000 payment as adequate compensation against an expert market valuation of $58,000. Other decisions have refused easements where reasonable necessity was not shown. Because the power is discretionary, even satisfying all four tests does not guarantee an order.
Which court, and when?
The Supreme Court has the general power under section 88K. The Land and Environment Court can exercise the same power under section 40 of its Act only where a development appeal is before it or has been determined by it. That makes timing strategic: a developer whose DA is under appeal can seek the easement in the same proceedings, while one with a council consent containing a deferred commencement condition would ordinarily approach the Supreme Court if negotiation fails.
How to approach a neighbour, and the steps if it fails
- At due diligence, confirm the site’s fall and whether gravity drainage to the street is possible; obtain survey levels and council pipe information.
- Identify the downhill lots that could carry an easement, and the shortest practical route to a council pipe.
- Have the engineer design the line, pipe size and pits, and estimate the disturbance to the neighbour’s land.
- Obtain a valuation of the easement’s impact so the offer is grounded in evidence.
- Approach the neighbour early with a written offer covering compensation, restoration, timing and their legal costs.
- Keep a record of every attempt; reasonable attempts to obtain the easement are a statutory requirement.
- If agreement fails, obtain legal advice on a section 88K or section 40 application, budgeting for compensation, costs and time.
Definitions
- Inter-allotment drainage easement
- A registered easement allowing stormwater from one lot to be piped across another to a lawful point of discharge.
- Section 88K
- The provision of the Conveyancing Act 1919 allowing the Supreme Court to impose an easement that is reasonably necessary for the effective use or development of land.
- Section 40 of the Land and Environment Court Act 1979
- The provision allowing the Land and Environment Court to impose an easement, applying the section 88K tests, in connection with a development appeal.
- Deferred commencement condition
- A condition under which a consent does not operate until specified matters, such as registration of an easement, are satisfied.
- Lawful point of discharge
- The location, such as a street kerb, council pipe or watercourse, to which stormwater may legally be discharged.
Frequently asked questions
Can my neighbour refuse a drainage easement?
Yes, they can refuse to agree. You can then apply to the court under section 88K of the Conveyancing Act 1919 (or section 40 of the Land and Environment Court Act if a development appeal is involved), but the court must be satisfied of the statutory tests and the order is discretionary.
How much compensation does a drainage easement cost?
It depends on the impact on the burdened land. Courts rely on valuation evidence; one 2026 case accepted $85,000 against a $58,000 market valuation. Applicants usually also pay the costs.
Can I use a pump instead of an easement?
Only if the council’s stormwater policy allows a charged or pump-out system for your type of development. Many councils restrict them for new multi-dwelling development.
When should I check drainage on a duplex site?
Before you buy. Survey levels and the council’s pipe network show quickly whether gravity drainage to the street is possible.
Stormwater discharge is one of the first feasibility checks in our development due diligence reports for duplex and townhouse sites, and our sister company Contrive Consultants designs the drainage solution and easement plans. For a downhill site, request a fee proposal before you commit.
Sources and references
- Conveyancing Act 1919, section 88K Power of Court to impose easements, accessed October 2026
- Lander & Rogers, Court-imposed easements: key lessons for developers and landowners, accessed October 2026
- Baron, When can a court order an easement? NSW decision provides guidance (August 2026), accessed October 2026
- NSW Department of Planning, Your guide to the DA process, Stage 4 Determination (deferred commencement), accessed October 2026
Information disclaimer. This article is general planning information prepared by the URBA Planning Team and is current at the date of publication. It is not planning, legal or financial advice for any specific property. Planning instruments, development control plans, state policies and the National Construction Code are amended regularly and councils interpret them differently; the controls quoted here should be confirmed against the versions in force at the date of lodgement and against the consent authority’s current requirements. Reliance on this article is at the reader’s own risk. URBA Planning, a division of Contrive Consultants Pty Ltd, accepts no liability for loss arising from its use. For advice on a specific site, contact URBA for a fee proposal.