Drainage Easements in NSW: Negotiation, s88K and Your Options

Stormwater runs downhill. That single fact decides more Sydney development outcomes than almost any planning control. If your site falls towards the street, your roof and surface water drains to the kerb or the council system and nobody thinks about it again. If your site falls away from the street, your lawful discharge point is probably downhill — through somebody else’s land — and you have just met the drainage easement.

Councils and certifiers will not approve a development without a lawful point of stormwater discharge. For low-side lots, battle-axe blocks and rear dwellings, that usually means securing an inter-allotment drainage easement over one or more downstream properties. This guide covers when you need one, how the negotiation with neighbours actually works, and what happens when negotiation fails: an application to the court under section 88K of the Conveyancing Act 1919.

What a drainage easement actually is

An easement is a registered right over someone else’s land — here, the right to drain water through a defined strip of the neighbour’s property, usually via an underground pipe, to a lawful discharge point such as a council pit, street drainage or a watercourse. The easement is recorded on both titles: the downstream lot is the burdened land, yours is the benefited land. It runs with the land permanently — future owners are bound by and benefit from it — and it typically carries rights of access for construction and maintenance of the pipe within the easement width.

The easement is created either by agreement (a transfer granting easement, or via a s88B instrument on a plan) or, failing agreement, by court order. Either way, a registered surveyor defines the easement site and a civil engineer designs the drainage line that will occupy it, generally to AS/NZS 3500.3 and the council’s engineering requirements.

When do you need one?

The trigger is simple: your development cannot lawfully dispose of stormwater within your own site or to the street by gravity. Common scenarios:

Low-side lots — the land falls from the street to the rear, so roof water cannot gravity-drain to the kerb.
Battle-axe and rear-lot subdivisions — the rear lot has no street frontage to drain to; Torrens subdivision approvals routinely condition an inter-allotment easement.
Duplex and dual occupancy projects — the rear dwelling sits below street level, or subdivision requires each lot to drain independently.
Basements and large hard-surface additions — increased runoff or seepage that on-site measures cannot lawfully deal with.

Some councils accept alternatives in limited circumstances — charged (pump-out) systems for small extensions, absorption/infiltration systems where soils genuinely permit, or on-site dispersal for minor works. Policies differ sharply between councils and are generally conservative for new dwellings and subdivisions. Do not assume an alternative will be accepted: get the council’s position, through your civil engineer, before you design around it.

Find out at feasibility, not after lodgement

The costliest version of this problem is the one discovered after the DA is designed and lodged. A stormwater feasibility assessment at site-selection stage will establish the fall of the land, the location of council drainage, any existing easements on the downstream titles (some subdivisions already have them — check the s88B instruments), and whether a gravity outlet exists. If an easement is needed, that shapes the project budget, the programme and even the purchase decision.

Negotiating with the neighbour

There is no compulsory acquisition here — your neighbour is under no obligation to grant an easement, and the law expects you to make a genuine attempt to reach agreement before any court will help you. Practical guidance from projects that have gone well (and badly):

Approach early and personally. A courteous conversation before any letters land is worth a great deal. Neighbours who first learn of your project via a legal letter start defensive and stay defensive.
Bring real information. An engineer-prepared concept showing the easement location (usually along a boundary), pipe alignment and depth, the construction footprint and the reinstatement scope answers the questions the neighbour will reasonably ask. Vague requests breed suspicion.
Offer proper compensation. The neighbour is granting a permanent property right. Compensation typically reflects any diminution in their land’s value, disturbance during construction, and often a share of their reasonable legal and valuation costs so they are not out of pocket for considering your request. A valuer can help frame a defensible figure.
Minimise the burden. Route along boundaries, keep the easement as narrow as the engineering allows, commit to reinstating landscaping and surfaces, and time works considerately. The cheaper the easement is to live with, the cheaper it is to buy.
Document it properly. Solicitors for both sides, clear easement terms (maintenance responsibility, access conditions), and registration on title. A handshake is not a drainage easement.

Most easements are secured this way. Budget genuinely for compensation and costs — attempting to secure a permanent right over someone’s backyard for a token amount is the most common negotiation failure we see.

When negotiation fails: section 88K

Section 88K of the Conveyancing Act 1919 empowers the Supreme Court of NSW to impose an easement over land without the owner’s consent (the Land and Environment Court can also exercise an equivalent power in certain development-related proceedings). It is a genuine remedy — courts grant drainage easements under s88K regularly — but it is a last resort with real hurdles. The court must be satisfied, in substance, that:

the easement is reasonably necessary for the effective use or development of your land;
the use of your land with the easement is not inconsistent with the public interest;
the burdened owner can be adequately compensated for any loss or disadvantage; and
you have made all reasonable attempts to obtain the easement by agreement.

Two consequences follow for how you run the whole process. First, your negotiation record matters legally — genuine offers, engineering information provided, reasonable compensation proposed. Second, expect to pay: the court will almost invariably order compensation to the burdened owner, and the applicant ordinarily pays the proceedings’ costs (including, in the usual course, the neighbour’s reasonable costs), unless unreasonable conduct by the neighbour shifts the balance. A s88K application also needs proper evidence — survey, engineering design, valuation — and adds months to a programme. It is a tool to have in reserve, and its existence often motivates settlement; it is not a shortcut around a fair negotiation.

Design, construction and the paperwork tail

Once the easement is agreed or ordered, the remaining steps are procedural but must be sequenced correctly:

Survey definition — the registered surveyor prepares the plan defining the easement site for registration.
Detailed drainage design — pipe size, grade, pits and connection detail to the lawful discharge point, submitted with your CC or CDC documentation.
Registration — the easement must be registered with NSW Land Registry Services; councils and certifiers generally require registration (or at minimum the executed instruments) before relevant certificates are released.
Construction and reinstatement — build per design, protect the neighbour’s property, reinstate as promised, and obtain works-as-executed documentation and engineering certification.

Frequently asked questions

Can my neighbour simply refuse a drainage easement?

They can refuse to negotiate — no one can force them to agree. But if the easement is reasonably necessary for your development and you have genuinely attempted agreement with proper compensation, the Supreme Court can impose one under s88K of the Conveyancing Act 1919. In practice, most matters settle once both sides understand that framework.

How much compensation should I offer?

There is no fixed scale. Compensation usually reflects the impact on the burdened land’s value, disturbance, and the neighbour’s reasonable costs of advice. Courts assess it on evidence, and a valuer’s opinion is the sensible anchor for an offer. For a typical boundary-aligned residential drainage easement the land-value impact is often modest — the goodwill and costs components are frequently what get the deal done.

Is a pump-out system an alternative to an easement?

Sometimes. Some councils accept charged or pump-out systems for minor development such as small additions, but most are reluctant for new dwellings and will not accept them for subdivisions, because pumps fail and the obligation is permanent. Council policy varies — confirm the position for your site before relying on it.

What if there is already a drainage easement behind my property?

Check the title and the s88B instrument of the original subdivision: if your lot is benefited, you may connect per the easement terms and the council’s requirements. If the easement benefits other lots but not yours, you may need the burdened owner’s agreement (and potentially the other parties’) to use or extend it — legal advice is worthwhile before assuming access.

Contrive Consultants assesses stormwater disposal at feasibility, designs inter-allotment drainage, and prepares the engineering evidence for easement negotiations and s88K applications across Greater Sydney. Explore our services, call +61 497 848 111, email info@contriveconsultants.com.au or contact us before your low-side site becomes a lodged-DA problem.