Easements and Sewer Mains: The Line on Your Title That Decides What You Can Build

The line on your title that decides what you can build

Most people buy land by walking it. Frontage, aspect, the neighbours, whether the backyard gets sun.

Almost nobody reads the deposited plan properly, and the deposited plan is where the bad news lives.

An easement is a right someone else holds over part of your land. You own the dirt. They own the right to have something in it, or to get to it. Most commonly in Sydney that's drainage — a sewer main or a stormwater line running through your block, often to serve properties uphill from you that have nothing to do with your build.

It is not a technicality. An easement across the middle of a block can take a duplex site and turn it into a single-dwelling site, and it can do that without changing a single thing about the zoning that made the block look attractive in the first place.

I've watched people spend real money on concept drawings for a block they were never going to be able to build that way. Every time, the information was sitting on the title from the day they bought it.

Easement, and the thing that's worse than an easement

There are two separate problems and people mix them up constantly.

A registered easement shows on your title and on the deposited plan. It has a defined width and position. You can see it. It's honest with you. You plan around it.

An unregistered main does not show on your title at all. Sydney Water has assets running under private land all over the older parts of Sydney that predate the current registration regime. Your title is clean. Your block still has a sewer main under it.

The second one is the one that hurts, because the only way to find it is to go looking. A Sydney Water sewer service diagram — the thing people call a diagram or a service print — shows the mains in relation to your property. It costs very little and takes almost no time. Ordering one before you commit to a block is one of the highest-value few dollars in this entire industry, and the number of people who skip it is remarkable.

A related trap: the diagram tells you roughly where the main runs. It does not tell you how deep it is. Depth is what determines whether you can build over it, pier around it, or not at all — and depth needs a CCTV inspection or a peg-out to establish properly.

You can sometimes build over it. That's the part people get wrong in both directions

Two camps here and both are wrong.

Camp one hears 'sewer main' and assumes the block is dead. It often isn't. Sydney Water has a build-over process. Structures can be approved over or near assets, subject to conditions, and it happens routinely.

Camp two hears 'you can build over it' and assumes it's a formality. It isn't. Approval comes with engineering — piered footings designed to transfer load below the zone of influence of the pipe, minimum clearances, sometimes encasement, sometimes a requirement to divert the main entirely at your cost.

The honest position is in between: it's usually possible and it's rarely free. What you're negotiating is cost and time, not permission in principle.

What drives the number is depth and what the asset is. A shallow stormwater line near a boundary is a manageable design problem. A deep sewer main running diagonally under the middle of the footprint, with a maintenance structure on it, is a different conversation — that's the one where diverting the main can cost more than the uplift you were chasing by building two dwellings instead of one.

And the timeline matters as much as the money. Build-over approval is a separate process running alongside your development approval. Start it late and it sits on the critical path while you pay holding costs on a block you can't touch.

The other easements nobody checks

Sewer gets the attention. It's not the only one.

Right of carriageway. Someone else has a legal right to drive across your land, usually to reach a battle-axe lot behind you. You cannot build on it and you generally cannot obstruct it, which includes during construction — try staging a build when a neighbour has a registered right to drive through your site every day.

Easement for support. Common on sloping sites and in older subdivisions. Constrains excavation near a boundary because a neighbouring structure relies on your ground staying where it is. Directly relevant if your design involves cutting into the site.

Electricity easement. Overhead or underground. Clearance requirements from an overhead line will quietly cap your building height or push the envelope sideways.

Restrictions on the use of land. Not an easement strictly, but it sits in the same part of the title and does the same damage. An 88B instrument can dictate roof materials, minimum floor areas, fencing types, or that only one dwelling may be erected on the lot. That last one is the killer — a covenant restricting the block to a single dwelling will happily sit on a block the council would otherwise let you develop. State planning reforms opened up what's *permissible*; they didn't reach into private covenants on your title.

That combination catches people out badly right now. The zone says two. The title says one. The title is not overridden by your excitement.

What a proper site check actually looks at

This is the sequence I'd want on any block before anyone commits money to design. It's not long and it's not expensive relative to what it protects.

Pull the title and read the second schedule — every easement, covenant and restriction, with the 88B instrument if one is referenced. Not a summary from an agent. The document.

Order the Sydney Water sewer service diagram and locate the mains. If anything runs through the footprint you're contemplating, establish depth before you go further.

Check the deposited plan against reality on site. Fences move over decades. What's fenced is not always what's owned, and a survey will tell you whether the block you walked is the block you're buying.

Overlay the planning constraints — flood planning level, bushfire attack level, heritage or conservation area, acid sulfate soils depending on where you are.

Confirm frontage and whether the driveway crossover can physically go where the design assumes, including pit and pole positions in the verge, which are not yours to move for free.

Then, and only then, is it worth talking about what you're going to build. Do it in that order and the design responds to the site. Do it the other way around and you spend months making the site fit a drawing it was never going to fit.

That sequence is exactly what /advisory/land-assessment exists to run, and it's the same discipline behind /tools/feasibility-check.

If you've already bought and you're only reading this now

Don't panic, and don't assume the worst.

Order the diagram and read the title properly this week, before you spend anything else. Most blocks come back fine or manageable. The ones that don't, you want to know about now rather than after you've paid for design.

If something is there, the questions in order are: what is it, where exactly, how deep, and who owns it. Answer those four and a competent builder or engineer can tell you fairly quickly whether you're looking at a design adjustment, a build-over application, a diversion, or a genuine rethink.

What I'd avoid is the middle path people default to — pressing on with design while telling yourself you'll sort the easement out later. Later is when it's expensive. An easement discovered at concept stage is a constraint you design around. The same easement discovered at engineering is a redesign, and discovered at construction it's a variation with your programme already burning.

The land doesn't care what you planned. Better to find out what it'll actually carry while you still have every option open. If you want the same discipline applied to the numbers rather than the dirt, /insights/nsw-low-mid-rise-housing-reforms-2026 covers what the zoning will and won't give you.